docs: def hash(self):
          """Hash value based on file name and content"""
          if self._hash is None:
              tohash = [self.path.name]
              # Hash a maximum of ~1MB of the hdf5 file
              tohash.append(hashfile(self.path, blocksize=65536, count=20))
              self._hash = hashobj(tohash)
          return self._hash