@classmethod
def parse(cls, obj, **kwargs):
    """Attempt to parse `obj` as a type description defined in the
        Mongotron mini-language. If `obj` is unrecognizable, return ``None``,
        otherwise return a :py:class:`Field` instance describing it.

            `obj`:
                The mini-language object to attempt to parse.

            `kwargs`:
                Extra keyword arguments passed to Field's constructor on
                success.
        """
    if obj is None:
        return cls(**kwargs)
