Error in documentation of the add_workflow() function

The documentation of the WFEngine class states that it is possible to add a workflow, that already exists in the launchpad, to the engine.

Using the add_workflow(fw_id) function as indicated will lead to the error 'ConfigurationException: workflow must be instance of Workflow or Firework'. The value of fw_id needs to be passed as keyword argument.

The correct argument for the function should be something like: wfe.add_workflow(fw_id=id_of_the_fw)

Where 'id_of_the_fw' refers to a firework-id which is part of the workflow one wishes to add to the engine.