diff --git a/xarray/plot/plot.py b/xarray/plot/plot.py
index ca68f617144..5c754c3f49b 100644
--- a/xarray/plot/plot.py
+++ b/xarray/plot/plot.py
@@ -288,7 +288,7 @@ def line(
         )
 
     # The allargs dict passed to _easy_facetgrid above contains args
-    if args is ():
+    if args == ():
         args = kwargs.pop("args", ())
     else:
         assert "args" not in kwargs