comment about stable api

Author: FBruzzesi

packages/python/plotly/plotly/express/_core.py

@@ -8,14 +8,19 @@
 from plotly.colors import qualitative, sequential
 import math
 
-import narwhals.stable.v1 as nw
-
 from plotly._subplots import (
     make_subplots,
     _set_trace_grid_reference,
     _subplot_type_for_trace_type,
 )
 
+import narwhals.stable.v1 as nw
+
+# The reason to use narwhals.stable.v1 is to have a stable and perfectly
+# backwards-compatible API, hence the confidence to not pin the Narwhals version exactly,
+# allowing for multiple major libraries to have Narwhals as a dependency without
+# forbidding users to install them all together due to dependency conflicts.
+
 NO_COLOR = "px_no_color_constant"