diff --git a/fieldExtraction/src/investment/investment_postprocessing_funcs.py b/fieldExtraction/src/investment/investment_postprocessing_funcs.py
index e1e5eb8..ee200e7 100644
--- a/fieldExtraction/src/investment/investment_postprocessing_funcs.py
+++ b/fieldExtraction/src/investment/investment_postprocessing_funcs.py
@@ -79,8 +79,13 @@ def flatten_singleton_string_list(list_str: str) -> str:
     try:
         # Convert the string to a list using ast.literal_eval
         list_obj = ast.literal_eval(list_str)
+        # Check if list_obj is actually a list
+        if not isinstance(list_obj, list):
+            return list_str
+        # If the list has one element, return that element
         if len(list_obj) == 1:
             return list_obj[0]
+        # Otherwise, return the list as a string
         return ", ".join(list_obj)
     except (ValueError, SyntaxError):
         return list_str
diff --git a/fieldExtraction/tests/investment_postprocess_test.py b/fieldExtraction/tests/investment_postprocess_test.py
index 9cfdb52..ca97131 100644
--- a/fieldExtraction/tests/investment_postprocess_test.py
+++ b/fieldExtraction/tests/investment_postprocess_test.py
@@ -40,6 +40,7 @@ class TestPostprocessFunctions(unittest.TestCase):
     def test_flatten_singleton_string_list(self):
         self.assertEqual(flatten_singleton_string_list("['123']"), "123")
         self.assertEqual(flatten_singleton_string_list("['123', '456']"), "123, 456")
+        self.assertEqual(flatten_singleton_string_list("11"), "11")
         self.assertEqual(flatten_singleton_string_list("invalid"), "invalid")
         self.assertEqual(flatten_singleton_string_list(None), "")