don't use curly braced initializer

python/dune/perftool/loopy/temporary.py

@@ -36,7 +36,7 @@ def _default_value(shape_impl, shape):
 
     t = _temporary_type(shape_impl, shape)
     if shape_impl[0] in ['fv', 'fm', 'vec']:
-        return "{0}{{{1}}}".format(t, _default_value(shape_impl[1:], shape[1:]))
+        return "{0}({1})".format(t, _default_value(shape_impl[1:], shape[1:]))
 
 
 def default_declaration(name, kernel, decl_info):