<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def GetPublicCert(self):
 """Download Gitkit public cert. Returns: dict of public certs. """


    cert_url = self.google_api_url + 'publicKeys'

    resp, content = self.http.request(cert_url)
    if resp.status == 200:
      return simplejson.loads(content)
    else:
      raise errors.GitkitServerError('Error response for cert url: %s' %
                                     content)