use implicit defaults for nodes

Co-authored-by: @neutrinoceros

Author: DanielYang59

cmasher/tests/test_utils.py

@@ -99,7 +99,7 @@ def test_combine_cmaps(self, cmaps, nodes):
 
     # Test combine cmaps with default nodes
     def test_default_nodes(self):
-        combined_cmap = combine_cmaps("Blues", "Oranges", nodes=None, n_rgb_levels=256)
+        combined_cmap = combine_cmaps("Blues", "Oranges", n_rgb_levels=256)
 
         blues_cmap = mpl.colormaps["Blues"]
         oranges_cmap = mpl.colormaps["Oranges"]