@classmethod
def initialize(cls, locales: 'typing.Dict[str, str]', initial_lang: str):
    """Initialize LocaleBorg.

        locales: dict with custom locale name overrides.
        """
    if not initial_lang:
        raise ValueError('Unknown initial language {0}'.format(initial_lang))
    cls.reset()
    cls.locales = locales
    cls.__initial_lang = initial_lang
    cls.initialized = True
