Example of how custom dragonfly commands could be configured

cfg_overrides.py

class Key:
    """Mock class."""
    def __init__(self, phrase):
        self._phrase = phrase


class Function:
    """ Mock class."""
    def __init__(self, phrase):
        self._phrase = phrase


def snake_case_count():
    """Mock method."""
    pass

# ------------------------------------

defaults = {
    'up [<n>]': Key("up:%(n)d"),
    'down [<n>]': Key("down:%(n)d"),
    'enter [<n>]': Key("enter:%(n)d"),
    'snake case <n> [words]': Function(snake_case_count),
    'parens': Key("lparen, rparen, left/3"),
    "tab [<n>]": Key("tab:%(n)d"),
    "delete [<n>]": Key("del/3:%(n)d")
}

custom_phrases = {
    'up [<n>]': 'blipp [<n>]',
    'down [<n>]': 'blorp [<n>]',
    'enter [<n>]': 'slap [<n>]',
    'snake case <n> [words]': 'underscore <n> [words]',
    'parens': None  # Disables the command.
}


def apply_custom_phrases(defaults, custom_phrases):
    for key, new_key in custom_phrases.items():
        if new_key is None:
            del defaults[key]
            continue
        if not key in defaults.keys():
            print('Warning, unknown phrase: "{}"'.format(key))
            continue
        defaults[new_key] = defaults[key]
        del defaults[key]


if __name__ == '__main__':
    apply_custom_phrases(defaults, custom_phrases)
    print('{')
    for key, value in defaults.items():
        print('    "{}", "{}",'.format(key, str(value)))
    print('}')

""" Produces:
{
    "underscore <n> [words]", "<__main__.Function object at 0x7f85001e8dd8>",
    "blipp [<n>]", "<__main__.Key object at 0x7f8500293668>",
    "slap [<n>]", "<__main__.Key object at 0x7f85001e83c8>",
    "tab [<n>]", "<__main__.Key object at 0x7f85001e8b70>",
    "blorp [<n>]", "<__main__.Key object at 0x7f85001e8a90>",
    "delete [<n>]", "<__main__.Key object at 0x7f85001e8e80>",
}
"""

In other words: the keys of the default dictionary has been replaced by the values from custom_phrases. This allows the user to redefine default phrases and disable default commands. The values in the default dictionary remain unchanged.