def stay(node, taken):
"""Used when parent chooses an action that is NOT None"""
child_t = node.t
child_env = snapshot(node.env, node.t)
child_env.removed_container[child_t].update(taken)
child_acts = remove_taken(node.actions, taken)
return Node(parent=node,
t=child_t,
env=child_env,
taken=taken,
actions=tuple(child_acts),
reward=0)
def test_remove_taken(exp, tak, tru):
assert set(remove_taken(exp, tak)) == tru