code: def do_execute(self):
          
          data = self.input.payload
          search = self.config["search"].shallow_copy()
          evl = self.config["eval"].shallow_copy()
          asel = attsel.AttributeSelection()
          asel.search(search)
          asel.evaluator(evl)
          asel.select_attributes(data)
          cont = AttributeSelectionContainer(
              original=data,
              reduced=asel.reduce_dimensionality(data),
              num_atts=asel.number_attributes_selected,
              selected=asel.selected_attributes,
              results=asel.results_string)
          self._output.append(Token(cont))
          return None
docs: The actual execution of the actor.
  
          :return: None if successful, otherwise error message
          :rtype: str