code: def fit(self, sequences, y=None):
          
          super(BACE, self).fit(sequences, y=y)
          if self.n_macrostates is not None:
              self._do_lumping()
          else:
              raise RuntimeError('n_macrostates must not be None to fit')
  
          return self
docs: Fit a BACE lumping model using a sequence of cluster assignments.
  
          Parameters
          ----------
          sequences : list(np.ndarray(dtype='int'))
              List of arrays of cluster assignments
          y : None
              Unused, present for sklearn compatibility only.
  
          Returns
          -------
          self