Reformat wrapper generation code

Signed-off-by: Ryan Everett <ryan.everett@arm.com>
diff --git a/tests/scripts/generate_psa_wrappers.py b/tests/scripts/generate_psa_wrappers.py
index 816dd5f..9ca6b29 100755
--- a/tests/scripts/generate_psa_wrappers.py
+++ b/tests/scripts/generate_psa_wrappers.py
@@ -145,7 +145,8 @@
         # Proof-of-concept: just instrument one function for now
         if function_name == 'psa_cipher_encrypt':
             return True
-        if function_name == 'psa_key_derivation_output_bytes' or function_name == 'psa_key_derivation_input_bytes':
+        if function_name in ('psa_key_derivation_output_bytes',
+                             'psa_key_derivation_input_bytes'):
             return True
         if function_name in ('psa_import_key',
                              'psa_export_key',