code: def _check_service_requirements(self):
          
          missing = self.services.get_missing_services(
              self.required_services.keys()
          )
          if missing:
              self.log.critical(
                  "Following services are required and missing: {}".format(
                      ', '.join(missing)
                  )
              )
              return False
          return True
docs: Final comparison of provided and required modules