diff --git a/tests/scripts/tf_psa_crypto_test_case_info.py b/tests/scripts/tf_psa_crypto_test_case_info.py
index b369c54981..3413805af4 100644
--- a/tests/scripts/tf_psa_crypto_test_case_info.py
+++ b/tests/scripts/tf_psa_crypto_test_case_info.py
@@ -12,6 +12,7 @@
 # built with `re.compile`. Always include the `re` module so that we
 # don't keep adding and removing it as the matchers evolve.
 import re #pylint: disable=unused-import
+from typing import Dict, List, Pattern, Union
 
 # Test cases that it makes sense not to execute in Mbed TLS. Typically
 # this is because they relate to implementation details of TF-PSA-Crypto,
@@ -24,7 +25,7 @@
 # - a regex, which must match the full test case description.
 # A test suite with no "." matches all test suites with the same .function
 # file. A test suite with a "." only matches that specific .data file.
-INTERNAL_TEST_CASES = {
+INTERNAL_TEST_CASES: Dict[str, List[Union[str, Pattern]]] = {
     'test_suite_config.crypto_combinations': [
         'Config: entropy: NV seed only',
     ],