"Permute sequences: as a list or generator of values"

def permute1(seq):
    if not seq:                               # Shuffle any sequence: list
        return [seq]                          # Empty sequence
    else:
        res = []
        for i in range(len(seq)):
            rest = seq[:i] + seq[i+1:]        # Delete current node
            for x in permute1(rest):          # Permute the others
                res.append(seq[i:i+1] + x)    # Add node at front
        return res

def permute2(seq):
    if not seq:                               # Shuffle any sequence: generator
        yield seq                             # Empty sequence
    else:
        for i in range(len(seq)):
            rest = seq[:i] + seq[i+1:]        # Delete current node
            for x in permute2(rest):          # Permute the others
                yield seq[i:i+1] + x          # Add node at front