AmazonWarehousingAndDistribution.list_inventory() next_token unusual problems

[zyzjian]

When I obtain data, I find that the next_token returned by each page request is the same, resulting in duplicate data obtained through next_token
my code：
def get_data(self, next_token):

    req_data = self.awd.list_inventory(

        next_token=next_token,

        maxResults=200

    )

    next_token = req_data.next_token

    self.data_list += req_data.payload['inventory']

    if req_data.next_token is not None:

        self.get_data(next_token)

    else:

        return self.data_list