import struct


def vox_size_content( x_size: int, y_size: int, z_size: int ) -> bytes:
  """Produces the content for the SIZE chunk. It contains the dimensions for a
  single model.
  """
  assert( x_size > 0 and y_size > 0 and z_size > 0 and x_size <= 126 and y_size <= 126 and z_size <= 126 )
  return struct.pack( '<III', x_size, y_size, z_size )