def load(self, requirements_file=None):
        """Load or reload requirements from a requirements.txt file.

        :param requirements_file: if not given, the filename used from
            initialization will be read again.
        """
        if requirements_file is None:
            requirements_file = self.filename
            if requirements_file is None:
                raise ValueError("no filename provided")
        elif isinstance(requirements_file, text_type):
            requirements_file = Path(requirements_file)
        self.clear()
        with requirements_file.open() as f:
            self.loads(f.read())

        if isinstance(requirements_file, (text_type, Path)):
            self.filename = requirements_file
def test():
    start = time.time()
    treap = None
    s = set()
    for i in range(100000):
        key = random.randint(0, 10000)
        if random.randint(0, 1) == 0:
            if key in s:
                treap = remove(treap, key)
                s.remove(key)
        elif key not in s:
            treap = insert(treap, key)
            s.add(key)
        assert len(s) == size(treap)

    for i in range(size(treap)):
        assert kth(treap, i) in s
    print(time.time() - start)