Влад

def is_circular(self):
    turtle = self.head
    rabbit = self.head
    while(turtle and rabbit and rabbit.next):
        turtle = turtle.next
        rabbit = rabbit.next.next
        if turtle == rabbit:
            return True
    return False

methods = [method for method in dir(set) if not method.startswith("_")]
for method in methods:
    func = getattr(set, method)
    func()

with open("log.txt") as infile:
    for line in infile:
        do_something_with(line)