code: def test_wrong_number_of_training_epochs(self):
      network = algorithms.GradientDescent(
          layers.Input(2) > layers.Sigmoid(1),
          verbose=False,
          batch_size=None,
      )
  
      with self.assertRaisesRegexp(ValueError, "a positive number"):
          network.train(np.zeros((4, 2)), np.zeros((4, 1)), epochs=0)
  
      with self.assertRaisesRegexp(ValueError, "a positive number"):
          network.train(np.zeros((4, 2)), np.zeros((4, 1)), epochs=-1)
  
file_path: neupy/tests/algorithms/test_network_features.py
imports: from __future__ import unicode_literals
  import numpy
  from sklearn import datasets
  from neupy import algorithms, layers
  from neupy.algorithms.base import preformat_value
  from helpers import catch_stdout
  from base import BaseTestCase
label_desc: Use image node_id 3 for calling the NetworkMainTestCase obj's underlying member method code with example usage: obj.test_wrong_number_of_training_epochs() without return types