diff --git a/xesmf/frontend.py b/xesmf/frontend.py
index f4dd45db..6100ff52 100644
--- a/xesmf/frontend.py
+++ b/xesmf/frontend.py
@@ -1032,8 +1032,8 @@ def _init_para_regrid(self, ds_in, ds_out, kwargs):
 
         # Rename coords to avoid issues in xr.map_blocks
         for coord in list(self.out_coords.keys()):
-            ds_out = ds_out.rename({coord:coord+'_out'})
-            
+            ds_out = ds_out.rename({coord: coord + '_out'})
+
         weights_dims = ('y_out', 'x_out', 'y_in', 'x_in')
         templ = sps.zeros((self.shape_out + self.shape_in))
         w_templ = xr.DataArray(templ, dims=weights_dims).chunk(