Repeat list

Implement the class RepeatList with the following methods:

• add(x): add the number x to the list
• check(): return True if some number repeats on the list, otherwise False

The time complexity of each method should be O(1).

In a file repeatlist.py, implement a class RepeatList according to the following template:

class RepeatList:
    def __init__(self):
        # TODO

    def add(self, x):
        # TODO

    def check(self):
        # TODO

if __name__ == "__main__":
    r = RepeatList()
    print(r.check()) # False
    r.add(1)
    r.add(2)
    r.add(3)
    print(r.check()) # False
    r.add(2)
    print(r.check()) # True
    r.add(5)
    print(r.check()) # True