def _list_outputs(self):
outputs = self.output_spec().get()
for name in outputs.keys():
coresponding_input = getattr(self.inputs, name)
if isdefined(coresponding_input):
if isinstance(coresponding_input, bool) and coresponding_input == True:
outputs[name] = os.path.abspath(self._outputs_filenames[name])
else:
outputs[name] = coresponding_input
return outputs