How to use the docopt.Either function in docopt

while groups:
        children = groups.pop(0)
        parents = [Required, Optional, OptionsShortcut, Either, OneOrMore]
        if any(t in map(type, children) for t in parents):
            child = [c for c in children if type(c) in parents][0]
            children.remove(child)
            if type(child) is Either:
                for c in child.children:
                    groups.append([c] + children)
            elif type(child) is OneOrMore:
                groups.append(child.children * 2 + children)
            else:
                groups.append(child.children + children)
        else:
            result.append(children)
    return Either(*[Required(*e) for e in result])

while groups:
        children = groups.pop(0)
        parents = [Required, Optional, OptionsShortcut, Either, OneOrMore]
        if any(t in map(type, children) for t in parents):
            child = [c for c in children if type(c) in parents][0]
            children.remove(child)
            if type(child) is Either:
                for c in child.children:
                    groups.append([c] + children)
            elif type(child) is OneOrMore:
                groups.append(child.children * 2 + children)
            else:
                groups.append(child.children + children)
        else:
            result.append(children)
    return Either(*[Required(*e) for e in result])

def parse_expr(tokens, options):
    """expr ::= seq ( '|' seq )* ;"""
    seq = parse_seq(tokens, options)
    if tokens.current() != '|':
        return seq
    result = [Required(*seq)] if len(seq) > 1 else seq
    while tokens.current() == '|':
        tokens.move()
        seq = parse_seq(tokens, options)
        result += [Required(*seq)] if len(seq) > 1 else seq
    return [Either(*result)] if len(result) > 1 else result

def transform(pattern):
    """Expand pattern into an (almost) equivalent one, but with single Either.

    Example: ((-a | -b) (-c | -d)) => (-a -c | -a -d | -b -c | -b -d)
    Quirks: [-a] => (-a), (-a...) => (-a -a)

    """
    result = []
    groups = [[pattern]]
    while groups:
        children = groups.pop(0)
        parents = [Required, Optional, OptionsShortcut, Either, OneOrMore]
        if any(t in map(type, children) for t in parents):
            child = [c for c in children if type(c) in parents][0]
            children.remove(child)
            if type(child) is Either:
                for c in child.children:
                    groups.append([c] + children)
            elif type(child) is OneOrMore:
                groups.append(child.children * 2 + children)
            else:
                groups.append(child.children + children)
        else:
            result.append(children)
    return Either(*[Required(*e) for e in result])

def parse_expr(tokens, options):
    """expr ::= seq ( '|' seq )* ;"""
    seq = parse_seq(tokens, options)
    if tokens.current() != '|':
        return seq
    result = [Required(*seq)] if len(seq) > 1 else seq
    while tokens.current() == '|':
        tokens.move()
        seq = parse_seq(tokens, options)
        result += [Required(*seq)] if len(seq) > 1 else seq
    return [Either(*result)] if len(result) > 1 else result