def extract_version(txt):
    """This function tries to extract the version from the help text of any
    program."""
    words = txt.replace(",", " ").split()
    version = None
    for x in reversed(words):
        if len(x) > 2:
            if x[0].lower() == "v":
                x = x[1:]
            if "." in x and x[0].isdigit():
                version = x
                break
    return version