'Remove collaborator ``username`` from the repository.
:param username: (required), login name of the collaborator
:type username: str or :class:`User <github3.users.User>`
:returns: bool'

@requires_auth
def remove_collaborator(self, username):

    if (not username):
        return False
    url = self._build_url(u'collaborators', str(username), base_url=self._api)
    return self._boolean(self._delete(url), 204, 404)
