docs: def is_memmappable(self):
          """Return if page's image data in file can be memory-mapped."""
          return (self.parent.filehandle.is_file and self.is_final and
                  # (self.bitspersample == 8 or self.parent.isnative) and
                  self.is_contiguous[0] % self.dtype.itemsize == 0)