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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 _FormatHumanReadableSize(self, size):
 """Represents a number of bytes as a human readable string. Args: size (int):
 size in bytes. Returns: str: human readable string of the size. """

    magnitude_1000 = 0
    size_1000 = float(size)
    while size_1000 >= 1000:
      size_1000 /= 1000
      magnitude_1000 += 1

    magnitude_1024 = 0
    size_1024 = float(size)
    while size_1024 >= 1024:
      size_1024 /= 1024
      magnitude_1024 += 1

    size_string_1000 = None
    if 0 < magnitude_1000 <= 7:
      size_string_1000 = '{0:.1f}{1:s}'.format(
          size_1000, self._UNITS_1000[magnitude_1000])

    size_string_1024 = None
    if 0 < magnitude_1024 <= 7:
      size_string_1024 = '{0:.1f}{1:s}'.format(
          size_1024, self._UNITS_1024[magnitude_1024])

    if not size_string_1000 or not size_string_1024:
      return '{0:d} B'.format(size)

    return '{0:s} / {1:s} ({2:d} B)'.format(
        size_string_1024, size_string_1000, size)