Merge pull request #1557 from nipy/fix_command_line

Changed default for CommandLine._run_interface to not be mutable

Author: satra

nipype/interfaces/base.py

@@ -1660,7 +1660,7 @@ def _run_wrapper(self, runtime):
         runtime = self._run_interface(runtime)
         return runtime
 
-    def _run_interface(self, runtime, correct_return_codes=[0]):
+    def _run_interface(self, runtime, correct_return_codes=(0,)):
         """Execute command via subprocess
 
         Parameters