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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fit(self, sequences, y=None):
 """Fit the clustering on the data 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. Returns ------- self """

        check_iter_of_sequences(sequences, allow_trajectory=self._allow_trajectory)
        super(MultiSequenceClusterMixin, self).fit(self._concat(sequences))

        if hasattr(self, 'labels_'):
            self.labels_ = self._split(self.labels_)

        return self