code: def metadata_response(self, request, full_url, headers):
          
  
          parsed_url = urlparse(full_url)
          tomorrow = datetime.datetime.utcnow() + datetime.timedelta(days=1)
          credentials = dict(
              AccessKeyId="test-key",
              SecretAccessKey="test-secret-key",
              Token="test-session-token",
              Expiration=tomorrow.strftime("%Y-%m-%dT%H:%M:%SZ")
          )
  
          path = parsed_url.path
  
          meta_data_prefix = "/latest/meta-data/"
          # Strip prefix if it is there
          if path.startswith(meta_data_prefix):
              path = path[len(meta_data_prefix):]
  
          if path == '':
              result = 'iam'
          elif path == 'iam':
              result = json.dumps({
                  'security-credentials': {
                      'default-role': credentials
                  }
              })
          elif path == 'iam/security-credentials/':
              result = 'default-role'
          elif path == 'iam/security-credentials/default-role':
              result = json.dumps(credentials)
          else:
              raise NotImplementedError(
                  "The {0} metadata path has not been implemented".format(path))
          return 200, headers, result
docs: Mock response for localhost metadata
  
          http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AESDG-chapter-instancedata.html