Fix Python backward compatibility tests
diff --git a/tools/interop_matrix/client_matrix.py b/tools/interop_matrix/client_matrix.py
index 730fe64..e39fabe 100644
--- a/tools/interop_matrix/client_matrix.py
+++ b/tools/interop_matrix/client_matrix.py
@@ -358,4 +358,14 @@
     'ruby_v1.0.1': 'ruby__v1.0.1',
     'csharp_v1.1.4': 'csharp__v1.1.4',
     'csharp_v1.2.5': 'csharp__v1.1.4',
+    'python_v1.0.x': 'python__v1.0.x',
+    'python_v1.1.4': 'python__v1.0.x',
+    'python_v1.2.5': 'python__v1.0.x',
+    'python_v1.3.9': 'python__v1.0.x',
+    'python_v1.4.2': 'python__v1.0.x',
+    'python_v1.6.6': 'python__v1.0.x',
+    'python_v1.7.2': 'python__v1.0.x',
+    'python_v1.8.1': 'python__v1.0.x',
+    'python_v1.9.1': 'python__v1.0.x',
+    'python_v1.10.0': 'python__v1.0.x',
 }