code: def crc(self):
          
          # will make sure everything has been transferred
          # to datastore that needs to be before returning crc
  
          result = self._data.fast_hash()
          if hasattr(self.mesh, 'crc'):
              # bitwise xor combines hashes better than a sum
              result ^= self.mesh.crc()
          return result
docs: A checksum for the current visual object and its parent mesh.
  
          Returns
          ----------
          crc: int, checksum of data in visual object and its parent mesh