code: def _minimize(self):
      self.opt_op = self.optimizer.minimize(self.loss)
  
imports: from collections import namedtuple
  import tensorflow
  import math
  import graphsage.layers
  import graphsage.metrics
  from .prediction import BipartiteEdgePredLayer
  from .aggregators import MeanAggregator, MaxPoolingAggregator, MeanPoolingAggregator, SeqAggregator, GCNAggregator
label_desc: Use image node_id 4 for calling the Node2VecModel obj's underlying member method code with example usage: obj._minimize() without return types