fix(interface): fields were being replaced in outputs call
A copy of the fields list was necessary for the default behaviour to work (i.e., there's only one input image called ``in_file`` and the corresponding output is ``out_file``).
@@ -58,7 +58,7 @@ class CopyXForm(SimpleInterface):
def _outputs(self):
base = super(CopyXForm, self)._outputs()
if self._fields:
- fields = self._fields
+ fields = self._fields.copy()
if 'in_file' in fields:
idx = fields.index('in_file')
fields.pop(idx)
