move the extract_constant outside the canonical_form function so that I can

theano/tensor/basic.py

@@ -2607,18 +2607,7 @@ def get_idx_list(inputs, idx_list):
     return cdata
 
 
-
-def get_canonical_form_slice(theslice, length):
-    '''
-    Given a slice [start:stop:step] transform it into a canonical form
-    that respects the conventions imposed by python and numpy.
-
-    In a canonical form a slice is represented by a canonical form slice,
-    in which the start <= stop and step >0 and a flag which says if the
-    resulting set of numbers needs to be reversed or not.
-   '''
-
-    def extract_constant(x):
+def extract_constant(x):
     '''
      This function is basically a call to tensor.get_constant_value. The
      main difference is the behaviour in case of failure. While
@@ -2637,6 +2626,18 @@ def get_canonical_form_slice(theslice, length):
             x = tensor.tensor_from_scalar(x)
     return x
 
+
+def get_canonical_form_slice(theslice, length):
+    '''
+    Given a slice [start:stop:step] transform it into a canonical form
+    that respects the conventions imposed by python and numpy.
+
+    In a canonical form a slice is represented by a canonical form slice,
+    in which the start <= stop and step >0 and a flag which says if the
+    resulting set of numbers needs to be reversed or not.
+   '''
+
+
     if isinstance(theslice,slice):
 
         start = extract_constant(theslice.start)