def compare(self, base, head):
assert isinstance(base, (str, unicode)), base<EOL>assert isinstance(head, (str, unicode)), head<EOL>headers, data = self._requester.requestJsonAndCheck(<EOL>"<STR_LIT:GET>",<EOL>self.url + "<STR_LIT>" + base + "<STR_LIT>" + head<EOL>)<EOL>return github.Comparison.Comparison(self._requester, headers, data, completed=True)<EOL>
:calls: `GET /repos/:owner/:repo/compare/:base...:head <http://developer.github.com/v3/repos/commits>`_
:param base: string
:param head: string
:rtype: :class:`github.Comparison.Comparison`