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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 GetTimeRange(cls):
 """Return the first and last timestamp of filter range."""

    first = getattr(cls, '_lower', 0)
    last = getattr(cls, '_upper', cls.MAX_INT64)

    if first < last:
      return first, last

    return last, first