code: def set_completer(self, completer):
          
  
          if not issubclass(completer.__class__, QCompleter):
              raise foundations.exceptions.ProgrammingError("{0} | '{1}' is not a 'QCompleter' subclass!".format(
                  self.__class__.__name__, completer))
  
          if self.__completer:
              self.remove_completer()
  
          LOGGER.debug("> Setting '{0}' completer.".format(completer))
          self.__completer = completer
          self.__completer.setWidget(self)
  
          # Signals / Slots.
          self.__completer.activated.connect(self.__insert_completion)
  
          return True
docs: Sets given completer as the current completer.
  
          :param completer: Completer.
          :type completer: QCompleter
          :return: Method success.
          :rtype: bool