Return NotImplemented for unsupported comparisons

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Fixed
 - Update `numpy.percentile` syntax to stop using deprecated alias [[5483](https://github.com/plotly/plotly.py/pull/5483)], with thanks to @Mr-Neutr0n for the contribution!
   - `numpy` with a version less than 1.22 is no longer supported.
+- The `__eq__` method for  `graph_objects` classes now returns `NotImplemented` to give the other operand an opportunity to handle the comparison.
 
 ## [6.6.0] - 2026-03-02
 

plotly/basedatatypes.py

@@ -789,7 +789,7 @@ def __contains__(self, prop):
     def __eq__(self, other):
         if not isinstance(other, BaseFigure):
             # Require objects to both be BaseFigure instances
-            return False
+            return NotImplemented
         else:
             # Compare plotly_json representations
 
@@ -5017,7 +5017,7 @@ def __eq__(self, other):
         """
         if not isinstance(other, self.__class__):
             # Require objects to be of the same plotly type
-            return False
+            return NotImplemented
         else:
             # Compare plotly_json representations
 

tests/test_core/test_graph_objs/test_figure_properties.py

@@ -1,4 +1,5 @@
 from unittest import TestCase
+from unittest.mock import MagicMock
 import pytest
 
 import plotly.graph_objs as go
@@ -42,6 +43,15 @@ def test_contains(self):
     def test_iter(self):
         self.assertEqual(set(self.figure), {"data", "layout", "frames"})
 
+    def test_unsupported_eq_returns_not_implemented(self):
+        other = MagicMock()
+        self.assertFalse(self.figure == other)
+        other.__eq__.assert_called_once_with(self.figure)
+
+        other.reset_mock()
+        self.assertFalse(self.figure.layout == other)
+        other.__eq__.assert_called_once_with(self.figure.layout)
+
     def test_attr_item(self):
         # test that equal objects can be retrieved using attr or item
         # syntax