docs: def transformation_get(node_id):
      """Get all the transformations of a node.
  
      The node id must be specified in the url.
  
      You can also pass transformation_type.
      """
      exp = Experiment(session)
  
      # get the parameters
      transformation_type = request_parameter(
          parameter="transformation_type",
          parameter_type="known_class",
          default=models.Transformation,
      )
      if type(transformation_type) == Response:
          return transformation_type
  
      # check the node exists
      node = models.Node.query.get(node_id)
      if node is None:
          return error_response(
              error_type="/node/transformations, "
              "node {} does not exist".format(node_id)
          )
  
      # execute the request
      transformations = node.transformations(type=transformation_type)
      try:
          # ping the experiment
          exp.transformation_get_request(node=node, transformations=transformations)
          session.commit()
      except Exception:
          return error_response(
              error_type="/node/transformations GET failed", participant=node.participant
          )
  
      # return the data
      return success_response(transformations=[t.__json__() for t in transformations])