diff --git a/cpsat_log_parser/blocks/search_progress.py b/cpsat_log_parser/blocks/search_progress.py
index 892052c..5fbb4e2 100644
--- a/cpsat_log_parser/blocks/search_progress.py
+++ b/cpsat_log_parser/blocks/search_progress.py
@@ -178,7 +178,7 @@ def parse(line: str) -> typing.Optional["ModelEvent"]:
         else:
             return None
 
-def _parse_version(lines: list[str]) -> tuple[int, int, int]:
+def _parse_version(lines: typing.List[str]) -> typing.Tuple[int, int, int]:
     """
     Parse the version of OR-Tools from log lines.
 
@@ -200,7 +200,7 @@ def _parse_version(lines: list[str]) -> tuple[int, int, int]:
     
     raise ValueError("Could not parse version from log")
 
-def apply_ortools911_workaround(lines: list[str]) -> list[str]:
+def apply_ortools911_workaround(lines: typing.List[str]) -> typing.List[str]:
     """
     Workaround for OR-Tools 9.11 to remove empty lines before the search progress block.
 
diff --git a/requirements.txt b/requirements.txt
index 07e3595..49a64e1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
 pandas>=2.0.0
 plotly==5.18.0
 streamlit>=1.30.0
+ortools
\ No newline at end of file