code: def _byte_pad(data, bound=4):
      
      bound = int(bound)
      if len(data) % bound != 0:
          pad = bytes(bound - (len(data) % bound))
          result = bytes().join([data, pad])
          assert (len(result) % bound) == 0
          return result
  
      return data
docs: GLTF wants chunks aligned with 4- byte boundaries
      so this function will add padding to the end of a
      chunk of bytes so that it aligns with a specified
      boundary size
  
      Parameters
      --------------
      data : bytes
        Data to be padded
      bound : int
        Length of desired boundary
  
      Returns
      --------------
      padded : bytes
        Result where: (len(padded) % bound) == 0