code: def fit(self, sequences, y=None):
          
          super(PCCA, self).fit(sequences, y=y)
          self._do_lumping()
          return self
docs: Fit a PCCA 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