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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 parse_stack_pointer(sp):
 """ Convert multiple supported forms of stack pointer representations into stack offsets. :param sp: A stack pointer representation. :return: A stack pointer offset. :rtype: int """

    if isinstance(sp, int):
        return sp

    if isinstance(sp, StackBaseOffset):
        return sp.offset

    if isinstance(sp, BinaryOp):
        op0, op1 = sp.operands
        off0 = parse_stack_pointer(op0)
        off1 = parse_stack_pointer(op1)
        if sp.op == "Sub":
            return off0 - off1
        elif sp.op == "Add":
            return off0 + off1

    raise NotImplementedError("Unsupported stack pointer representation type %s." % type(sp))