code: def check(self, action, version=None):
          
          if action not in self._by_action:
              raise APIError(400, "InvalidAction", "The action %s is not valid "
                             "for this web service." % action)
          by_version = self._by_action[action]
          if None not in by_version:
              # There's no catch-all method, let's try the version-specific one
              if version not in by_version:
                  raise APIError(400, "InvalidVersion", "Invalid API version.")
docs: Check if the given action is supported in the given version.
  
          @raises APIError: If there's no method class registered for handling
              the given action or version.