code: def cast(self, mapping):
          
          # See 'citation' method in
          # http://docutils.sourceforge.net/docutils/parsers/rst/states.py
          for c, p in mapping.items():
              self.doc.note_citation(c)
              self.doc.note_explicit_target(c, c)
              c.persona = p
              self.log.debug("{0} to be played by {1}".format(
                  c["names"][0].capitalize(), p)
              )
          return self
docs: Allocate the scene script a cast of personae for each of its entities.
  
          :param mapping: A dictionary of {Entity, Persona}
          :return: The SceneScript object.