fix: check for version and handle stdout/err

Author: satra

nipype/interfaces/base.py

@@ -1285,12 +1285,16 @@ def _process(drain=0):
         result['stdout'] = []
         result['stderr'] = []
         result['merged'] = ''
-    runtime.stderr = bytes('\n'.join(result['stderr']), 'utf-8').decode('utf-8')
-    runtime.stdout = bytes('\n'.join(result['stdout']), 'utf-8').decode('utf-8')
-    if isinstance(result['merged'], list):
-        runtime.merged = [bytes(val).decode('utf-8')
-                          for val in result['merged']]
+    if sys.version_info < (3,):
+        runtime.stderr = '\n'.join(result['stderr']).decode('utf-8')
+        runtime.stdout = '\n'.join(result['stdout']).decode('utf-8')
+        if isinstance(result['merged'], list):
+            runtime.merged = [val.decode('utf-8') for val in result['merged']]
+        else:
+            runtime.merged = result['merged']
     else:
+        runtime.stderr = '\n'.join(result['stderr'])
+        runtime.stdout = '\n'.join(result['stdout'])
         runtime.merged = result['merged']
     runtime.returncode = proc.returncode
     return runtime