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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 _num_bytes_to_human_readable(num_bytes):
 """Returns human readable string of how much memory `num_bytes` fills."""

  if num_bytes < (2 ** 10):
    return "%d B" % num_bytes
  elif num_bytes < (2 ** 20):
    return "%.3f KB" % (float(num_bytes) / (2 ** 10))
  elif num_bytes < (2 ** 30):
    return "%.3f MB" % (float(num_bytes) / (2 ** 20))
  else:
    return "%.3f GB" % (float(num_bytes) / (2 ** 30))