FIX: remove def _format_art for GTMPVC

Author: mnoergaard

nipype/interfaces/freesurfer/petsurfer.py

@@ -513,9 +513,6 @@ def _list_outputs(self):
 
         return outputs
 
-    def _format_arg(self, name, spec, value):
-        return super(GTMPVC, self)._format_arg(name, spec, value)
-
 
 class MRTMInputSpec(GLMFitInputSpec):
     mrtm1 = traits.Tuple(