diff --git a/scripts/dump_bin.py b/scripts/dump_bin.py
index 4811fd4861..d702c4038d 100644
--- a/scripts/dump_bin.py
+++ b/scripts/dump_bin.py
@@ -234,7 +234,7 @@ def _dump_bin(self, file_or_data: [Path, pd.DataFrame], calendar_list: List[pd.T
         if isinstance(file_or_data, pd.DataFrame):
             if file_or_data.empty:
                 return
-            code = fname_to_code(file_or_data.iloc[0][self.symbol_field_name].lower())
+            code = fname_to_code(str(file_or_data.iloc[0][self.symbol_field_name]).lower())
             df = file_or_data
         elif isinstance(file_or_data, Path):
             code = self.get_symbol_from_file(file_or_data)