code: def repr_size(n_bytes):
      
      if n_bytes < 1024:
          return '{0} Bytes'.format(n_bytes)
      i = -1
      while n_bytes > 1023:
          n_bytes /= 1024.0
          i += 1
      return '{0} {1}iB'.format(round(n_bytes, 1), si_prefixes[i])
docs: >>> repr_size(1000)
      '1000 Bytes'
      >>> repr_size(8257332324597)
      '7.5 TiB'