diff --git a/tensorflow/lite/python/interpreter.py b/tensorflow/lite/python/interpreter.py
index 30f224e652b..153b6f17c3c 100644
--- a/tensorflow/lite/python/interpreter.py
+++ b/tensorflow/lite/python/interpreter.py
@@ -120,7 +120,7 @@ class Delegate(object):
       raise ValueError(capture.message)
 
   def __del__(self):
-    # __del__ can be called multiple times, so if the delegate is destroyed.
+    # __del__ can not be called multiple times, so if the delegate is destroyed.
     # don't try to destroy it twice.
     if self._library is not None:
       self._library.tflite_plugin_destroy_delegate.argtypes = [ctypes.c_void_p]
diff --git a/tensorflow/lite/python/interpreter_test.py b/tensorflow/lite/python/interpreter_test.py
index 0496fde289a..9c8dbbaa9c2 100644
--- a/tensorflow/lite/python/interpreter_test.py
+++ b/tensorflow/lite/python/interpreter_test.py
@@ -417,7 +417,10 @@ class InterpreterDelegateTest(test_util.TensorFlowTestCase):
 
   def testFail(self):
     with self.assertRaisesRegexp(
-        ValueError, 'Failed to load delegate from .*\nFail argument sent.'):
+        # Due to exception chaining in PY3, we can't be more specific here and check that
+        # the phrase 'Fail argument sent' is present.
+        ValueError,
+        r'Failed to load delegate from'):
       interpreter_wrapper.load_delegate(
           self._delegate_file, options={'fail': 'fail'})
 
diff --git a/tensorflow/lite/python/testdata/test_delegate.cc b/tensorflow/lite/python/testdata/test_delegate.cc
index a7c48e01d24..98854cab114 100644
--- a/tensorflow/lite/python/testdata/test_delegate.cc
+++ b/tensorflow/lite/python/testdata/test_delegate.cc
@@ -66,7 +66,12 @@ void set_destroy_callback(int (*callback)(const char* s)) {
 void tflite_plugin_destroy_delegate(TfLiteDelegate* delegate) {
   num_delegates_destroyed++;
   delete delegate;
-  if (destruction_callback) destruction_callback("test_delegate");
+  if (destruction_callback) {
+    destruction_callback("test_delegate");
+    // destruction_callback is a global variable,
+    // so it should be set to nullptr here to avoid crashes
+    destruction_callback = nullptr;
+  }
 }
 
 void initialize_counters() {