code: def _verify_part_size(self):
          
          if self._part_size > PartSize.MAXIMUM_UPLOAD_SIZE:
              self._status = TransferState.FAILED
              raise SbgError('Part size = {}b. Maximum part size is {}b'.format(
                  self._part_size, PartSize.MAXIMUM_UPLOAD_SIZE)
              )
docs: Verifies that the part size is smaller then the maximum part size
          which is 5GB.