code: def sodium_increment(inp):
      
      ensure(isinstance(inp, bytes),
             raising=exc.TypeError)
  
      ln = len(inp)
      buf = ffi.new("unsigned char []", ln)
  
      ffi.memmove(buf, inp, ln)
  
      lib.sodium_increment(buf, ln)
  
      return ffi.buffer(buf, ln)[:]
docs: Increment the value of a byte-sequence interpreted
      as the little-endian representation of a unsigned big integer.
  
      :param inp: input bytes buffer
      :type inp: bytes
      :return: a byte-sequence representing, as a little-endian
               unsigned big integer, the value ``to_int(inp)``
               incremented by one.
      :rtype: bytes