code: def savestate(self, state, chain=-1):
          
          cur_chain = self._chains[chain]
          if hasattr(cur_chain, '_state_'):
              cur_chain._state_[0] = state
          else:
              s = self._h5file.create_vlarray(
                  cur_chain,
                  '_state_',
                  tables.ObjectAtom(),
                  title='The saved state of the sampler',
                  filters=self.filter)
              s.append(state)
          self._h5file.flush()
docs: Store a dictionnary containing the state of the Model and its
          StepMethods.