How to use the flask-api.User function in Flask-API

def load_user(request):
    auth_header = request.headers.get('X-Auth')
    token_header = request.headers.get('X-Auth-Token')
    data = []

    if auth_header is not None:
        (username, password) = auth_header.split(':')
        user_entry = User.get(username)
        if user_entry is not None:
            user = User(user_entry[0], user_entry[1], user_entry[2])
            if user.password == password:
                if token_header == user.token:
                    data =  login_serializer.loads(user.token)
                    token_user = User.get(data[0])
                    #Check Password and return user or None
                    if token_user == user_entry and data[1] == password:
                        return user
    return None