def iter_filths():
    """Iterate over all instances of filth"""
    for filth_cls in iter_filth_clss():
        if issubclass(filth_cls, RegexFilth):
            m = next(re.finditer(r"\s+", "fake pattern string"))
            yield filth_cls(m)
        else:
            yield filth_cls()
Iterate over all instances of filth