code: def fit(self, sequences, y=None):
              
              check_iter_of_sequences(sequences)
              for sequence in sequences:
                  s = super(MultiSequencePreprocessingMixin, self)
                  s.partial_fit(sequence)
  
              return self
docs: Fit Preprocessing to X.
  
              Parameters
              ----------
              sequences : list of array-like, each of shape [sequence_length, n_features]
                  A list of multivariate timeseries. Each sequence may have
                  a different length, but they all must have the same number
                  of features.
              y : None
                  Ignored
  
              Returns
              -------
              self