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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 unpack_qubit(qubit):
 """ Get a qubit from an object. :param qubit: An int or Qubit. :return: A Qubit instance """

    if isinstance(qubit, integer_types):
        return Qubit(qubit)
    elif isinstance(qubit, Qubit):
        return qubit
    elif isinstance(qubit, QubitPlaceholder):
        return qubit
    else:
        raise TypeError("qubit should be an int or Qubit instance")