Merge remote-tracking branch 'upstream/master'

1 files changed, 740 insertions, 0 deletions

diff --git a/lib/python/milc.py b/lib/python/milc.py
new file mode 100644
index 0000000000..e8599eff3f
--- /dev/null
+++ b/lib/python/milc.py
@@ -0,0 +1,740 @@
+#!/usr/bin/env python3
+# coding=utf-8
+"""MILC - A CLI Framework
+
+PYTHON_ARGCOMPLETE_OK
+
+MILC is an opinionated framework for writing CLI apps. It optimizes for the
+most common unix tool pattern- small tools that are run from the command
+line but generally do not feature any user interaction while they run.
+
+For more details see the MILC documentation:
+
+    <https://github.com/clueboard/milc/tree/master/docs>
+"""
+from __future__ import division, print_function, unicode_literals
+import argparse
+import logging
+import os
+import re
+import shlex
+import sys
+from decimal import Decimal
+from pathlib import Path
+from tempfile import NamedTemporaryFile
+from time import sleep
+
+try:
+    from ConfigParser import RawConfigParser
+except ImportError:
+    from configparser import RawConfigParser
+
+try:
+    import thread
+    import threading
+except ImportError:
+    thread = None
+
+import argcomplete
+import colorama
+from appdirs import user_config_dir
+
+# Disable logging until we can configure it how the user wants
+logging.basicConfig(stream=os.devnull)
+
+# Log Level Representations
+EMOJI_LOGLEVELS = {
+    'CRITICAL': '{bg_red}{fg_white}¬_¬{style_reset_all}',
+    'ERROR': '{fg_red}☒{style_reset_all}',
+    'WARNING': '{fg_yellow}⚠{style_reset_all}',
+    'INFO': '{fg_blue}ℹ{style_reset_all}',
+    'DEBUG': '{fg_cyan}☐{style_reset_all}',
+    'NOTSET': '{style_reset_all}¯\\_(o_o)_/¯'
+}
+EMOJI_LOGLEVELS['FATAL'] = EMOJI_LOGLEVELS['CRITICAL']
+EMOJI_LOGLEVELS['WARN'] = EMOJI_LOGLEVELS['WARNING']
+UNICODE_SUPPORT = sys.stdout.encoding.lower().startswith('utf')
+
+# ANSI Color setup
+# Regex was gratefully borrowed from kfir on stackoverflow:
+# https://stackoverflow.com/a/45448194
+ansi_regex = r'\x1b(' \
+             r'(\[\??\d+[hl])|' \
+             r'([=<>a-kzNM78])|' \
+             r'([\(\)][a-b0-2])|' \
+             r'(\[\d{0,2}[ma-dgkjqi])|' \
+             r'(\[\d+;\d+[hfy]?)|' \
+             r'(\[;?[hf])|' \
+             r'(#[3-68])|' \
+             r'([01356]n)|' \
+             r'(O[mlnp-z]?)|' \
+             r'(/Z)|' \
+             r'(\d+)|' \
+             r'(\[\?\d;\d0c)|' \
+             r'(\d;\dR))'
+ansi_escape = re.compile(ansi_regex, flags=re.IGNORECASE)
+ansi_styles = (
+    ('fg', colorama.ansi.AnsiFore()),
+    ('bg', colorama.ansi.AnsiBack()),
+    ('style', colorama.ansi.AnsiStyle()),
+)
+ansi_colors = {}
+
+for prefix, obj in ansi_styles:
+    for color in [x for x in obj.__dict__ if not x.startswith('_')]:
+        ansi_colors[prefix + '_' + color.lower()] = getattr(obj, color)
+
+
+def format_ansi(text):
+    """Return a copy of text with certain strings replaced with ansi.
+    """
+    # Avoid .format() so we don't have to worry about the log content
+    for color in ansi_colors:
+        text = text.replace('{%s}' % color, ansi_colors[color])
+    return text + ansi_colors['style_reset_all']
+
+
+class ANSIFormatter(logging.Formatter):
+    """A log formatter that inserts ANSI color.
+    """
+    def format(self, record):
+        msg = super(ANSIFormatter, self).format(record)
+        return format_ansi(msg)
+
+
+class ANSIEmojiLoglevelFormatter(ANSIFormatter):
+    """A log formatter that makes the loglevel an emoji on UTF capable terminals.
+    """
+    def format(self, record):
+        if UNICODE_SUPPORT:
+            record.levelname = EMOJI_LOGLEVELS[record.levelname].format(**ansi_colors)
+        return super(ANSIEmojiLoglevelFormatter, self).format(record)
+
+
+class ANSIStrippingFormatter(ANSIFormatter):
+    """A log formatter that strips ANSI.
+    """
+    def format(self, record):
+        msg = super(ANSIStrippingFormatter, self).format(record)
+        return ansi_escape.sub('', msg)
+
+
+class Configuration(object):
+    """Represents the running configuration.
+
+    This class never raises IndexError, instead it will return None if a
+    section or option does not yet exist.
+    """
+    def __contains__(self, key):
+        return self._config.__contains__(key)
+
+    def __iter__(self):
+        return self._config.__iter__()
+
+    def __len__(self):
+        return self._config.__len__()
+
+    def __repr__(self):
+        return self._config.__repr__()
+
+    def keys(self):
+        return self._config.keys()
+
+    def items(self):
+        return self._config.items()
+
+    def values(self):
+        return self._config.values()
+
+    def __init__(self, *args, **kwargs):
+        self._config = {}
+
+    def __getattr__(self, key):
+        return self.__getitem__(key)
+
+    def __getitem__(self, key):
+        """Returns a config section, creating it if it doesn't exist yet.
+        """
+        if key not in self._config:
+            self.__dict__[key] = self._config[key] = ConfigurationSection(self)
+
+        return self._config[key]
+
+    def __setitem__(self, key, value):
+        self.__dict__[key] = value
+        self._config[key] = value
+
+    def __delitem__(self, key):
+        if key in self.__dict__ and key[0] != '_':
+            del self.__dict__[key]
+        if key in self._config:
+            del self._config[key]
+
+
+class ConfigurationSection(Configuration):
+    def __init__(self, parent, *args, **kwargs):
+        super(ConfigurationSection, self).__init__(*args, **kwargs)
+        self.parent = parent
+
+    def __getitem__(self, key):
+        """Returns a config value, pulling from the `user` section as a fallback.
+        """
+        if key in self._config:
+            return self._config[key]
+
+        elif key in self.parent.user:
+            return self.parent.user[key]
+
+        return None
+
+
+def handle_store_boolean(self, *args, **kwargs):
+    """Does the add_argument for action='store_boolean'.
+    """
+    disabled_args = None
+    disabled_kwargs = kwargs.copy()
+    disabled_kwargs['action'] = 'store_false'
+    disabled_kwargs['dest'] = self.get_argument_name(*args, **kwargs)
+    disabled_kwargs['help'] = 'Disable ' + kwargs['help']
+    kwargs['action'] = 'store_true'
+    kwargs['help'] = 'Enable ' + kwargs['help']
+
+    for flag in args:
+        if flag[:2] == '--':
+            disabled_args = ('--no-' + flag[2:],)
+            break
+
+    self.add_argument(*args, **kwargs)
+    self.add_argument(*disabled_args, **disabled_kwargs)
+
+    return (args, kwargs, disabled_args, disabled_kwargs)
+
+
+class SubparserWrapper(object):
+    """Wrap subparsers so we can track what options the user passed.
+    """
+    def __init__(self, cli, submodule, subparser):
+        self.cli = cli
+        self.submodule = submodule
+        self.subparser = subparser
+
+        for attr in dir(subparser):
+            if not hasattr(self, attr):
+                setattr(self, attr, getattr(subparser, attr))
+
+    def completer(self, completer):
+        """Add an arpcomplete completer to this subcommand.
+        """
+        self.subparser.completer = completer
+
+    def add_argument(self, *args, **kwargs):
+        """Add an argument for this subcommand.
+
+        This also stores the default for the argument in `self.cli.default_arguments`.
+        """
+        if 'action' in kwargs and kwargs['action'] == 'store_boolean':
+            # Store boolean will call us again with the enable/disable flag arguments
+            return handle_store_boolean(self, *args, **kwargs)
+
+        self.cli.acquire_lock()
+        self.subparser.add_argument(*args, **kwargs)
+        if self.submodule not in self.cli.default_arguments:
+            self.cli.default_arguments[self.submodule] = {}
+        self.cli.default_arguments[self.submodule][self.cli.get_argument_name(*args, **kwargs)] = kwargs.get('default')
+        self.cli.release_lock()
+
+
+class MILC(object):
+    """MILC - An Opinionated Batteries Included Framework
+    """
+    def __init__(self):
+        """Initialize the MILC object.
+
+            version
+                The version string to associate with your CLI program
+        """
+        # Setup a lock for thread safety
+        self._lock = threading.RLock() if thread else None
+
+        # Define some basic info
+        self.acquire_lock()
+        self._description = None
+        self._entrypoint = None
+        self._inside_context_manager = False
+        self.ansi = ansi_colors
+        self.arg_only = []
+        self.config = None
+        self.config_file = None
+        self.default_arguments = {}
+        self.version = 'unknown'
+        self.release_lock()
+
+        # Figure out our program name
+        self.prog_name = sys.argv[0][:-3] if sys.argv[0].endswith('.py') else sys.argv[0]
+        self.prog_name = self.prog_name.split('/')[-1]
+
+        # Initialize all the things
+        self.read_config_file()
+        self.initialize_argparse()
+        self.initialize_logging()
+
+    @property
+    def description(self):
+        return self._description
+
+    @description.setter
+    def description(self, value):
+        self._description = self._arg_parser.description = value
+
+    def echo(self, text, *args, **kwargs):
+        """Print colorized text to stdout.
+
+        ANSI color strings (such as {fg-blue}) will be converted into ANSI
+        escape sequences, and the ANSI reset sequence will be added to all
+        strings.
+
+        If *args or **kwargs are passed they will be used to %-format the strings.
+        """
+        if args and kwargs:
+            raise RuntimeError('You can only specify *args or **kwargs, not both!')
+
+        args = args or kwargs
+        text = format_ansi(text)
+
+        print(text % args)
+
+    def initialize_argparse(self):
+        """Prepare to process arguments from sys.argv.
+        """
+        kwargs = {
+            'fromfile_prefix_chars': '@',
+            'conflict_handler': 'resolve',
+        }
+
+        self.acquire_lock()
+        self.subcommands = {}
+        self._subparsers = None
+        self.argwarn = argcomplete.warn
+        self.args = None
+        self._arg_parser = argparse.ArgumentParser(**kwargs)
+        self.set_defaults = self._arg_parser.set_defaults
+        self.print_usage = self._arg_parser.print_usage
+        self.print_help = self._arg_parser.print_help
+        self.release_lock()
+
+    def completer(self, completer):
+        """Add an argcomplete completer to this subcommand.
+        """
+        self._arg_parser.completer = completer
+
+    def add_argument(self, *args, **kwargs):
+        """Wrapper to add arguments and track whether they were passed on the command line.
+        """
+        if 'action' in kwargs and kwargs['action'] == 'store_boolean':
+            return handle_store_boolean(self, *args, **kwargs)
+
+        self.acquire_lock()
+
+        self._arg_parser.add_argument(*args, **kwargs)
+        if 'general' not in self.default_arguments:
+            self.default_arguments['general'] = {}
+        self.default_arguments['general'][self.get_argument_name(*args, **kwargs)] = kwargs.get('default')
+
+        self.release_lock()
+
+    def initialize_logging(self):
+        """Prepare the defaults for the logging infrastructure.
+        """
+        self.acquire_lock()
+        self.log_file = None
+        self.log_file_mode = 'a'
+        self.log_file_handler = None
+        self.log_print = True
+        self.log_print_to = sys.stderr
+        self.log_print_level = logging.INFO
+        self.log_file_level = logging.DEBUG
+        self.log_level = logging.INFO
+        self.log = logging.getLogger(self.__class__.__name__)
+        self.log.setLevel(logging.DEBUG)
+        logging.root.setLevel(logging.DEBUG)
+        self.release_lock()
+
+        self.add_argument('-V', '--version', version=self.version, action='version', help='Display the version and exit')
+        self.add_argument('-v', '--verbose', action='store_true', help='Make the logging more verbose')
+        self.add_argument('--datetime-fmt', default='%Y-%m-%d %H:%M:%S', help='Format string for datetimes')
+        self.add_argument('--log-fmt', default='%(levelname)s %(message)s', help='Format string for printed log output')
+        self.add_argument('--log-file-fmt', default='[%(levelname)s] [%(asctime)s] [file:%(pathname)s] [line:%(lineno)d] %(message)s', help='Format string for log file.')
+        self.add_argument('--log-file', help='File to write log messages to')
+        self.add_argument('--color', action='store_boolean', default=True, help='color in output')
+        self.add_argument('--config-file', help='The location for the configuration file')
+        self.arg_only.append('config_file')
+
+    def add_subparsers(self, title='Sub-commands', **kwargs):
+        if self._inside_context_manager:
+            raise RuntimeError('You must run this before the with statement!')
+
+        self.acquire_lock()
+        self._subparsers = self._arg_parser.add_subparsers(title=title, dest='subparsers', **kwargs)
+        self.release_lock()
+
+    def acquire_lock(self):
+        """Acquire the MILC lock for exclusive access to properties.
+        """
+        if self._lock:
+            self._lock.acquire()
+
+    def release_lock(self):
+        """Release the MILC lock.
+        """
+        if self._lock:
+            self._lock.release()
+
+    def find_config_file(self):
+        """Locate the config file.
+        """
+        if self.config_file:
+            return self.config_file
+
+        if '--config-file' in sys.argv:
+            return Path(sys.argv[sys.argv.index('--config-file') + 1]).expanduser().resolve()
+
+        filedir = user_config_dir(appname='qmk', appauthor='QMK')
+        filename = '%s.ini' % self.prog_name
+        return Path(filedir) / filename
+
+    def get_argument_name(self, *args, **kwargs):
+        """Takes argparse arguments and returns the dest name.
+        """
+        try:
+            return self._arg_parser._get_optional_kwargs(*args, **kwargs)['dest']
+        except ValueError:
+            return self._arg_parser._get_positional_kwargs(*args, **kwargs)['dest']
+
+    def argument(self, *args, **kwargs):
+        """Decorator to call self.add_argument or self.<subcommand>.add_argument.
+        """
+        if self._inside_context_manager:
+            raise RuntimeError('You must run this before the with statement!')
+
+        def argument_function(handler):
+            if 'arg_only' in kwargs and kwargs['arg_only']:
+                arg_name = self.get_argument_name(*args, **kwargs)
+                self.arg_only.append(arg_name)
+                del kwargs['arg_only']
+
+            name = handler.__name__.replace("_", "-")
+            if handler is self._entrypoint:
+                self.add_argument(*args, **kwargs)
+
+            elif name in self.subcommands:
+                self.subcommands[name].add_argument(*args, **kwargs)
+
+            else:
+                raise RuntimeError('Decorated function is not entrypoint or subcommand!')
+
+            return handler
+
+        return argument_function
+
+    def arg_passed(self, arg):
+        """Returns True if arg was passed on the command line.
+        """
+        return self.default_arguments.get(arg) != self.args[arg]
+
+    def parse_args(self):
+        """Parse the CLI args.
+        """
+        if self.args:
+            self.log.debug('Warning: Arguments have already been parsed, ignoring duplicate attempt!')
+            return
+
+        argcomplete.autocomplete(self._arg_parser)
+
+        self.acquire_lock()
+        self.args = self._arg_parser.parse_args()
+
+        if 'entrypoint' in self.args:
+            self._entrypoint = self.args.entrypoint
+
+        self.release_lock()
+
+    def read_config_file(self):
+        """Read in the configuration file and store it in self.config.
+        """
+        self.acquire_lock()
+        self.config = Configuration()
+        self.config_file = self.find_config_file()
+
+        if self.config_file and self.config_file.exists():
+            config = RawConfigParser(self.config)
+            config.read(str(self.config_file))
+
+            # Iterate over the config file options and write them into self.config
+            for section in config.sections():
+                for option in config.options(section):
+                    value = config.get(section, option)
+
+                    # Coerce values into useful datatypes
+                    if value.lower() in ['1', 'yes', 'true', 'on']:
+                        value = True
+                    elif value.lower() in ['0', 'no', 'false', 'off']:
+                        value = False
+                    elif value.lower() in ['none']:
+                        continue
+                    elif value.replace('.', '').isdigit():
+                        if '.' in value:
+                            value = Decimal(value)
+                        else:
+                            value = int(value)
+
+                    self.config[section][option] = value
+
+        self.release_lock()
+
+    def merge_args_into_config(self):
+        """Merge CLI arguments into self.config to create the runtime configuration.
+        """
+        self.acquire_lock()
+        for argument in vars(self.args):
+            if argument in ('subparsers', 'entrypoint'):
+                continue
+
+            if argument not in self.arg_only:
+                # Find the argument's section
+                if self._entrypoint.__name__ in self.default_arguments and argument in self.default_arguments[self._entrypoint.__name__]:
+                    argument_found = True
+                    section = self._entrypoint.__name__
+                if argument in self.default_arguments['general']:
+                    argument_found = True
+                    section = 'general'
+
+                if not argument_found:
+                    raise RuntimeError('Could not find argument in `self.default_arguments`. This should be impossible!')
+                    exit(1)
+
+                # Merge this argument into self.config
+                if argument in self.default_arguments:
+                    arg_value = getattr(self.args, argument)
+                    if arg_value:
+                        self.config[section][argument] = arg_value
+                else:
+                    if argument not in self.config[section]:
+                        self.config[section][argument] = getattr(self.args, argument)
+
+        self.release_lock()
+
+    def save_config(self):
+        """Save the current configuration to the config file.
+        """
+        self.log.debug("Saving config file to '%s'", str(self.config_file))
+
+        if not self.config_file:
+            self.log.warning('%s.config_file file not set, not saving config!', self.__class__.__name__)
+            return
+
+        self.acquire_lock()
+
+        # Generate a sanitized version of our running configuration
+        config = RawConfigParser()
+        for section_name, section in self.config._config.items():
+            config.add_section(section_name)
+            for option_name, value in section.items():
+                if section_name == 'general':
+                    if option_name in ['config_file']:
+                        continue
+                if value is not None:
+                    config.set(section_name, option_name, str(value))
+
+        # Write out the config file
+        config_dir = self.config_file.parent
+        if not config_dir.exists():
+            config_dir.mkdir(parents=True, exist_ok=True)
+
+        with NamedTemporaryFile(mode='w', dir=str(config_dir), delete=False) as tmpfile:
+            config.write(tmpfile)
+
+        # Move the new config file into place atomically
+        if os.path.getsize(tmpfile.name) > 0:
+            os.rename(tmpfile.name, str(self.config_file))
+        else:
+            self.log.warning('Config file saving failed, not replacing %s with %s.', str(self.config_file), tmpfile.name)
+
+        # Housekeeping
+        self.release_lock()
+        cli.log.info('Wrote configuration to %s', shlex.quote(str(self.config_file)))
+
+    def __call__(self):
+        """Execute the entrypoint function.
+        """
+        if not self._inside_context_manager:
+            # If they didn't use the context manager use it ourselves
+            with self:
+                return self.__call__()
+
+        if not self._entrypoint:
+            raise RuntimeError('No entrypoint provided!')
+
+        return self._entrypoint(self)
+
+    def entrypoint(self, description):
+        """Set the entrypoint for when no subcommand is provided.
+        """
+        if self._inside_context_manager:
+            raise RuntimeError('You must run this before cli()!')
+
+        self.acquire_lock()
+        self.description = description
+        self.release_lock()
+
+        def entrypoint_func(handler):
+            self.acquire_lock()
+            self._entrypoint = handler
+            self.release_lock()
+
+            return handler
+
+        return entrypoint_func
+
+    def add_subcommand(self, handler, description, name=None, **kwargs):
+        """Register a subcommand.
+
+        If name is not provided we use `handler.__name__`.
+        """
+        if self._inside_context_manager:
+            raise RuntimeError('You must run this before the with statement!')
+
+        if self._subparsers is None:
+            self.add_subparsers()
+
+        if not name:
+            name = handler.__name__.replace("_", "-")
+
+        self.acquire_lock()
+
+        kwargs['help'] = description
+        self.subcommands[name] = SubparserWrapper(self, name, self._subparsers.add_parser(name, **kwargs))
+        self.subcommands[name].set_defaults(entrypoint=handler)
+
+        self.release_lock()
+
+        return handler
+
+    def subcommand(self, description, **kwargs):
+        """Decorator to register a subcommand.
+        """
+        def subcommand_function(handler):
+            return self.add_subcommand(handler, description, **kwargs)
+
+        return subcommand_function
+
+    def setup_logging(self):
+        """Called by __enter__() to setup the logging configuration.
+        """
+        if len(logging.root.handlers) != 0:
+            # MILC is the only thing that should have root log handlers
+            logging.root.handlers = []
+
+        self.acquire_lock()
+
+        if self.config['general']['verbose']:
+            self.log_print_level = logging.DEBUG
+
+        self.log_file = self.config['general']['log_file'] or self.log_file
+        self.log_file_format = self.config['general']['log_file_fmt']
+        self.log_file_format = ANSIStrippingFormatter(self.config['general']['log_file_fmt'], self.config['general']['datetime_fmt'])
+        self.log_format = self.config['general']['log_fmt']
+
+        if self.config.general.color:
+            self.log_format = ANSIEmojiLoglevelFormatter(self.args.log_fmt, self.config.general.datetime_fmt)
+        else:
+            self.log_format = ANSIStrippingFormatter(self.args.log_fmt, self.config.general.datetime_fmt)
+
+        if self.log_file:
+            self.log_file_handler = logging.FileHandler(self.log_file, self.log_file_mode)
+            self.log_file_handler.setLevel(self.log_file_level)
+            self.log_file_handler.setFormatter(self.log_file_format)
+            logging.root.addHandler(self.log_file_handler)
+
+        if self.log_print:
+            self.log_print_handler = logging.StreamHandler(self.log_print_to)
+            self.log_print_handler.setLevel(self.log_print_level)
+            self.log_print_handler.setFormatter(self.log_format)
+            logging.root.addHandler(self.log_print_handler)
+
+        self.release_lock()
+
+    def __enter__(self):
+        if self._inside_context_manager:
+            self.log.debug('Warning: context manager was entered again. This usually means that self.__call__() was called before the with statement. You probably do not want to do that.')
+            return
+
+        self.acquire_lock()
+        self._inside_context_manager = True
+        self.release_lock()
+
+        colorama.init()
+        self.parse_args()
+        self.merge_args_into_config()
+        self.setup_logging()
+
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.acquire_lock()
+        self._inside_context_manager = False
+        self.release_lock()
+
+        if exc_type is not None and not isinstance(SystemExit(), exc_type):
+            print(exc_type)
+            logging.exception(exc_val)
+            exit(255)
+
+
+cli = MILC()
+
+if __name__ == '__main__':
+
+    @cli.argument('-c', '--comma', help='comma in output', default=True, action='store_boolean')
+    @cli.entrypoint('My useful CLI tool with subcommands.')
+    def main(cli):
+        comma = ',' if cli.config.general.comma else ''
+        cli.log.info('{bg_green}{fg_red}Hello%s World!', comma)
+
+    @cli.argument('-n', '--name', help='Name to greet', default='World')
+    @cli.subcommand('Description of hello subcommand here.')
+    def hello(cli):
+        comma = ',' if cli.config.general.comma else ''
+        cli.log.info('{fg_blue}Hello%s %s!', comma, cli.config.hello.name)
+
+    def goodbye(cli):
+        comma = ',' if cli.config.general.comma else ''
+        cli.log.info('{bg_red}Goodbye%s %s!', comma, cli.config.goodbye.name)
+
+    @cli.argument('-n', '--name', help='Name to greet', default='World')
+    @cli.subcommand('Think a bit before greeting the user.')
+    def thinking(cli):
+        comma = ',' if cli.config.general.comma else ''
+        spinner = cli.spinner(text='Just a moment...', spinner='earth')
+        spinner.start()
+        sleep(2)
+        spinner.stop()
+
+        with cli.spinner(text='Almost there!', spinner='moon'):
+            sleep(2)
+
+        cli.log.info('{fg_cyan}Hello%s %s!', comma, cli.config.thinking.name)
+
+    @cli.subcommand('Show off our ANSI colors.')
+    def pride(cli):
+        cli.echo('{bg_red}                    ')
+        cli.echo('{bg_lightred_ex}                    ')
+        cli.echo('{bg_lightyellow_ex}                    ')
+        cli.echo('{bg_green}                    ')
+        cli.echo('{bg_blue}                    ')
+        cli.echo('{bg_magenta}                    ')
+
+    # You can register subcommands using decorators as seen above, or using functions like like this:
+    cli.add_subcommand(goodbye, 'This will show up in --help output.')
+    cli.goodbye.add_argument('-n', '--name', help='Name to bid farewell to', default='World')
+
+    cli()  # Automatically picks between main(), hello() and goodbye()