class_docstr: LightGCN model
  
  :Citation:
  
      He, Xiangnan, Kuan Deng, Xiang Wang, Yan Li, Yongdong Zhang, and Meng Wang.
      "LightGCN: Simplifying and Powering Graph Convolution Network for Recommendation." arXiv
      preprint arXiv:2002.02126, 2020.
code: def output_embeddings(self, idmapper, n, target, user_file):
      embeddings = list(target.eval(session=self.sess))
      with open(user_file, "w") as wt:
          for i in range(n):
              wt.write(
                  "{0}\t{1}\n".format(
                      idmapper[i],
                      " ".join([str(a) for a in embeddings[i]]),
                  )
              )
  
imports: import tensorflow
  import time
  import os
  import sys
  import numpy
  import pandas
  from recommenders.evaluation.python_evaluation import map_at_k, ndcg_at_k, precision_at_k, recall_at_k
  from recommenders.utils.python_utils import get_top_k_scored_items
label_desc: Use image node_id 11 for calling the LightGCN obj's underlying member method code with example usage: obj.output_embeddings(idmapper, n, target, user_file) without return types