code: def _validate(self, writing=False):
          
          if ((len(self.bits_per_component) != len(self.signed)) or
                  (len(self.signed) != self.palette.shape[1])):
              msg = ("The length of the 'bits_per_component' and the 'signed' "
                     "members must equal the number of columns of the palette.")
              self._dispatch_validation_error(msg, writing=writing)
          bps = self.bits_per_component
          if writing and not all(b == bps[0] for b in bps):
              # We don't support writing palettes with bit depths that are
              # different.
              msg = "Writing palettes with varying bit depths is not supported."
              self._dispatch_validation_error(msg, writing=writing)
docs: Verify that the box obeys the specifications.