code: def __init__(self):
      self.user = tf.placeholder(dtype=tf.int32, shape=(None,))
      self.item = tf.placeholder(dtype=tf.int32, shape=(None,))
      self.label = tf.placeholder(dtype=tf.int32, shape=(None,))
  
      feat = tf.stack([self.user, self.item], axis=1)
      self.logits = tf.layers.dense(tf.to_float(feat), 2)
  
      self.loss = tf.reduce_mean(
          tf.losses.sparse_softmax_cross_entropy(
              logits=self.logits, labels=self.label
          )
      )
  
imports: import os
  import shutil
  import tempfile
  from unittest import TestCase
  import numpy
  import tensorflow
  from zoo.orca.learn.trigger import SeveralIteration
  from pyspark.sql.context import SQLContext
  import zoo.orca.data.pandas
  from zoo import init_nncontext
  from zoo.orca import OrcaContext
  from zoo.orca.data.tf.data import Dataset
  from zoo.orca.learn.tf.estimator import Estimator
  from zoo.util.tf import save_tf_checkpoint, load_tf_checkpoint, get_checkpoint_state
label_desc: Use image node_id 1 to create a new SimpleModel object from inherited base classes: object with example: obj = SimpleModel()