'Iterate over all existing files in all registered paths.'

def __iter__(self):

    search = self.path[:]
    while search:
        path = search.pop()
        if (not os.path.isdir(path)):
            continue
        for name in os.listdir(path):
            full = os.path.join(path, name)
            if os.path.isdir(full):
                search.append(full)
            else:
                (yield full)
