Editing the workflow to be compatible python 2.7/3.x

Author: byvernault

nipype/workflows/smri/niftyreg/groupwise.py

@@ -8,6 +8,7 @@
 Including linear and non-linear image co-registration
 '''
 
+from builtins import str, range
 import nipype.interfaces.utility as niu
 import nipype.interfaces.niftyreg as niftyreg
 import nipype.pipeline.engine as pe
@@ -209,7 +210,7 @@ def create_nonlinear_gw_step(name="nonlinear_gw_niftyreg",
         workflow.connect(inputnode, 'input_aff_files', nonlin_reg, 'aff_file')
 
     if demean:
-        if 'vel_flag' in nonlinear_options_hash.keys() and \
+        if 'vel_flag' in list(nonlinear_options_hash.keys()) and \
            nonlinear_options_hash['vel_flag'] is True and \
            initial_affines:
             workflow.connect(