code: def make_uuid(cls, app_id=None):
          
          try:
              if app_id and isinstance(uuid.UUID(str(app_id), version=4), uuid.UUID):
                  return str(app_id)
          except (ValueError, AssertionError):
              pass
          return str(uuid.UUID(int=random.getrandbits(128)))
docs: Generates a new UUID.
          This is a class method and can be called as `Experiment.make_uuid()`.
          Takes an optional `app_id` which is converted to a string and, if it
          is a valid UUID, returned.