title: Theano AttributeError: 'module' object has no attribute 'tests'
body: <p>I have Keras installed with Theano backend and it worked fine while suddenly I get the following error while importing keras:</p>
  
  <pre><code>    Using Theano backend.
  ---------------------------------------------------------------------------
  AttributeError                            Traceback (most recent call last)
  &lt;ipython-input-2-570b835f182b&gt; in &lt;module&gt;()
        1 # import keras
  ----&gt; 2 from keras.preprocessing.image import ImageDataGenerator, array_to_img, img_to_array, load_img
        3 from keras.models import Sequential
        4 from keras.layers import Convolution2D, MaxPooling2D
        5 from keras.layers import Activation, Dropout, Flatten, Dense
  
  /home/pjwstk.edu.pl/s16352/python/keras/keras/__init__.py in &lt;module&gt;()
        1 from __future__ import absolute_import
  ----&gt; 2 from . import backend
        3 from . import datasets
        4 from . import engine
        5 from . import layers
  
  /home/pjwstk.edu.pl/s16352/python/keras/keras/backend/__init__.py in &lt;module&gt;()
       62 if _BACKEND == 'theano':
       63     sys.stderr.write('Using Theano backend.\n')
  ---&gt; 64     from .theano_backend import *
       65 elif _BACKEND == 'tensorflow':
       66     sys.stderr.write('Using TensorFlow backend.\n')
  
  /home/pjwstk.edu.pl/s16352/python/keras/keras/backend/theano_backend.py in &lt;module&gt;()
  ----&gt; 1 import theano
        2 from theano import tensor as T
        3 from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams
        4 from theano.tensor.signal import pool
        5 from theano.tensor.nnet import conv3d2d
  
  /home/pjwstk.edu.pl/s16352/python/Theano/theano/__init__.pyc in &lt;module&gt;()
       98 # needed during that phase.
       99 import theano.tests
  --&gt; 100 if hasattr(theano.tests, "TheanoNoseTester"):
      101     test = theano.tests.TheanoNoseTester().test
      102 else:
  
  AttributeError: 'module' object has no attribute 'tests'
  </code></pre>
  
  <p>I am running it in Jupyter notebooks on server. 
  Any clues?</p>