Returns the sequence of each `Polymer` in the `Assembly` as a list.

        Returns
        -------
        sequences : [str]
            List of sequences.

def sequences(self):
        """Returns the sequence of each `Polymer` in the `Assembly` as a list.

        Returns
        -------
        sequences : [str]
            List of sequences.
        """
        seqs = [x.sequence for x in self._molecules if hasattr(x, 'sequence')]
        return seqs