def connect_to_mongo(username='', password='', host='localhost', port=27017):
    credentials = ''
    if (username and password):
        credentials = f'{username}:{password}@'
    connection_url = f'mongodb://{credentials}{host}:{port}'
    return pymongo.MongoClient(connection_url)
def connect_to_mongo(username=, password=, host='localhost', port=27017):
    credentials = 
    if (username and password):
        credentials = f'{username}:{password}@'
    connection_url = f'mongodb://{credentials}{host}:{port}'
    return pymongo.MongoClient(connection_url)