':calls: `PATCH /repos/:owner/:repo/git/refs/:ref <http://developer.github.com/v3/git/refs>`_
:param sha: string
:param force: bool
:rtype: None'

def edit(self, sha, force=github.GithubObject.NotSet):

    assert isinstance(sha, (str, unicode)), sha
    assert ((force is github.GithubObject.NotSet) or isinstance(force, bool)), force
    post_parameters = {'sha': sha}
    if (force is not github.GithubObject.NotSet):
        post_parameters['force'] = force
    (headers, data) = self._requester.requestJsonAndCheck('PATCH', self.url, input=post_parameters)
    self._useAttributes(data)
