def assertHeader(self, key, value=None, msg=None):
        lowkey = key.lower()
        for k, v in self.headers:
            if k.lower() == lowkey:
                if value is None or str(value) == v:
                    return v

        if msg is None:
            if value is None:
                msg = '%r not in headers' % key
            else:
                msg = '%r:%r not in headers' % (key, value)
        self._handlewebError(msg)
Fail if (key, [value]) not in self.headers.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/cherrypy/cherrypy/test/webtest.py/WebCase.assertHeader