Makes S3DataGrabber change all paths from s3 to local

Previously, S3DataGrabber checked if outputs were lists or strings,
and changed them in those cases. However, if output was a unicode,
then it went unchanged. That's clearly not what we want, so we now
change in all cases: iterating through all values of output if it has
__iter__ attribute (is list-like), and using the value as the path if
it doesn't.

Author: billbrod

nipype/interfaces/io.py

@@ -656,14 +656,17 @@ def _list_outputs(self):
         # Outputs are currently stored as locations on S3.
         # We must convert to the local location specified
         # and download the files.
-        for key in outputs:
-            if type(outputs[key]) == list:
-                paths = outputs[key]
-                for i in range(len(paths)):
-                    path = paths[i]
+        for key,val in outputs.iteritems():
+            #This will basically be either list-like or string-like:
+            #if it has the __iter__ attribute, it's list-like (list,
+            #tuple, numpy array) and we iterate through each of its
+            #values. If it doesn't, it's string-like (string,
+            #unicode), and we convert that value directly.
+            if hasattr(val,'__iter__'):
+                for i,path in enumerate(val):
                     outputs[key][i] = self.s3tolocal(path, bkt)
-            elif type(outputs[key]) == str:
-                outputs[key] = self.s3tolocal(outputs[key], bkt)
+            else:
+                outputs[key] = self.s3tolocal(val, bkt)
 
         return outputs