fixed wrong default in Python os.getenv

Author: Sigrid Keydana

inst/python/kerastools/layer.py

@@ -1,7 +1,7 @@
 
 import os
 
-if (os.getenv('KERAS_IMPLEMENTATION', 'keras') == 'keras'):
+if (os.getenv('KERAS_IMPLEMENTATION', 'tensorflow') == 'keras'):
   from keras.engine.topology import Layer
   def shape_filter(shape):
     return shape

inst/python/kerastools/model.py

@@ -2,7 +2,7 @@
 
 import os
 
-if (os.getenv('KERAS_IMPLEMENTATION', 'keras') == 'keras'):
+if (os.getenv('KERAS_IMPLEMENTATION', 'tensorflow') == 'keras'):
   from keras.engine import Model
 else:
   try:

inst/python/kerastools/wrapper.py

@@ -1,6 +1,6 @@
 import os
 
-if (os.getenv('KERAS_IMPLEMENTATION', 'keras') == 'keras'):
+if (os.getenv('KERAS_IMPLEMENTATION', 'tensorflow') == 'keras'):
   from keras.layers import Wrapper
   def shape_filter(shape): 
     return shape