def forward(self, user, item):
    self.batch_size = item.shape[0]
    user_e = self.user_embedding(user)
    (entities, relations) = self.get_neighbors(item)
    item_e = self.aggregate(user_e, entities, relations)
    return (user_e, item_e)
def forward(self, user, item):
    self.batch_size = item.shape[0]
    user_e = self.user_embedding(user)
    (entities, relations) = self.get_neighbors(item)
    item_e = self.aggregate(user_e, entities, relations)
    return (user_e, item_e)