code: def toggleSelection(self, row, component):
          
          selection = self._parameters[row]['selection']
          if component in selection:
              selection.remove(component)
          else:
              selection.append(component)
docs: Toggles the *component* in or out of the selection 
          for parameter *row*
  
          :param row: the ith parameter number
          :type row: int
          :param component: the component to toggle its selection membership
          :type component: :class:`AbstractStimulusComponent<sparkle.stim.abstract_component.AbstractStimulusComponent>`