'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.'

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
