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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pop_stack(stack, op_id):
 """Proxy of pop, where we know we're popping a stack off of a stack. We know that we don't need to differentiate through this. See pop() for more. Args: stack: The stack to pop from. op_id: A unique variable that is also passed into the matching push. Allows optimization passes to track pairs of pushes and pops. Returns: The last value. """

  if __debug__:
    pushed_stack, pushed_op_id = stack.pop()
    assert pushed_op_id == op_id, 'Wanted %s, got %s' % (op_id, pushed_op_id)
  else:
    pushed_stack = stack.pop()
  return pushed_stack