code: def set_valid(self, boolean):
          '''
          Sets the state and calls the change if needed
          @param bool: The state (true or false)
          '''
          old_state = self.is_valid()
          self.valid_file = boolean
  
          if old_state != self.valid_file:
              self.call_valid(self.valid_filef set_valid(self, boolean):
          '''
          Sets the state and calls the change if needed
          @param bool: The state (true or false)
          '''
          old_state = self.is_valid()
          self.valid_file = boolean
  
          if old_state != self.valid_file:
              self.call_valid(self.valid_file)
docs: Sets the state and calls the change if needed
          @param bool: The state (true or false)