code: def testEmptyClasses(self):
      with test_util.use_gpu():
          x = random_ops.multinomial(array_ops.zeros([5, 0]), 7)
          with self.assertRaisesOpError(
              "num_classes should be positive"
          ):
              self.evaluate(x)
  
imports: import collections
  import timeit
  import numpy
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.python.client import session
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import random_seed
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import control_flow_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 15 for calling the MultinomialTest obj's underlying member method code with example usage: obj.testEmptyClasses() without return types