code: def append_state(self, s, is_widened_state=False):
          
  
          if not is_widened_state:
              self.all_states.append(s)
              self.state = s
  
          else:
              self.widened_state = s
docs: Appended a new state to this VFGNode.
          :param s: The new state to append
          :param is_widened_state: Whether it is a widened state or not.