def extract_transformers_from_source(source):
    """pass"""
    lines = source.split('\n')
    linenumbers = []
    for number, line in enumerate(lines):
        if FROM_EXPERIMENTAL.match(line):
            add_transformers(line)
            linenumbers.insert(0, number)
    for number in linenumbers:
        del lines[number]
    return '\n'.join(lines)