'Ensure that there\'s no token currently being parsed.
If there are unconsumed token contents, it means we hit an unexpected
token transition. In this case, we raise a TokenizerError'

def assert_empty_token(self):

    if self.token:
        raise TokenizerError(("Unexpected    character    at    position    %d    in    '%s'" % (self.offset, self.formula)))
