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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 _total_microsec(t1, t2):
 """ Calculate difference between two datetime stamps in microseconds. :type t1: :class: `datetime.datetime` :type t2: :class: `datetime.datetime` :return: int .. rubric:: Example -31536000000000 """

    td = t1 - t2
    return (td.seconds + td.days * 24 * 3600) * 10 ** 6 + td.microseconds