delete one of the spaces.  Can we add a property like `self._is_layered` or something similar instead?  Also, switch the test and the loop.

Perhaps something like:
````python
if self._is_layered:
   for arg in self.args if arg._is_indirect or arg._is_mat:
       for map in as_tuple(arg.map, Map) if map.offset is not None:
           _args.append(map.offset)
````