def METHOD_NAME(self, stream, seqs):
    i = 0
    for line in stream:
        line = line.rstrip()
        if not line:
            assert i == self._number_of_seqs
            i = 0
        else:
            seq = line.replace(" ", "")
            seqs[i].append(seq)
            i += 1
    if i != 0 and i != self._number_of_seqs:
        raise ValueError("Unexpected file format")