import time
from datetime import datetime, timedelta
from collections import defaultdict


class ExpiringMap:
    def __init__(self):
        self.data = defaultdict(dict)

    def put(self, key, value, expire_time):
        current_time = datetime.now()
        expire_timestamp = current_time + timedelta(seconds=expire_time)
        self.data[key] = {'value': value, 'expire_time': expire_timestamp}

    def get(self, key):
        current_time = datetime.now()
        if key in self.data and self.data[key]['expire_time'] > current_time:
            return self.data[key]['value']
        else:
            return None

    def remove(self, key):
        if key in self.data:
            del self.data[key]


if __name__ == "__main__":
    time_client_map = ExpiringMap()
    time_client_map.put('a', 'b', 10)
    time.sleep(5)
    print(time_client_map.get('a'))
    time.sleep(6)
    print(time_client_map.get('a'))