diff --git a/anonymize_data.py b/anonymize_data.py
index 089bf6a..f260e40 100644
--- a/anonymize_data.py
+++ b/anonymize_data.py
@@ -65,7 +65,7 @@ def get_review_token_indices(
 
 
 def get_author_name_token_index(
-    ballot_year: str = "2018",
+    ballot_year: str | int = "2018",
     *,
     is_anonymized: bool = False,
 ) -> int:
diff --git a/parsing_params.py b/parsing_params.py
index 0812cc5..996523b 100644
--- a/parsing_params.py
+++ b/parsing_params.py
@@ -48,11 +48,14 @@ def adjust_params_to_year(params: dict[str, dict], year: str | int) -> dict[str,
     return params
 
 
-def get_adjusted_parsing_params(year):
+def get_adjusted_parsing_params(year: str | int):
     return adjust_params_to_year(get_default_parsing_params(), year)
 
 
-def get_next_indices(last_index: int = 0, num_indices: int = 0) -> tuple[int, int, int]:
+def get_next_indices(
+    last_index: int = 0,
+    num_indices: int = 0,
+) -> tuple[int, int, int | None]:
     # The first index to include
     start = 1 + last_index
 
@@ -67,7 +70,7 @@ def get_next_indices(last_index: int = 0, num_indices: int = 0) -> tuple[int, in
 def convert_params_to_indices(
     params: dict[str, dict],
     offset: int = 9,
-) -> dict[str, dict]:
+) -> dict:
     voter_index = offset
 
     indices = {
@@ -108,9 +111,9 @@ def get_parsing_offset(*, is_anonymized: bool) -> int:
     return 0 if is_anonymized else 9
 
 
-def get_parsing_indices(year, is_anonymized):
+def get_parsing_indices(year: str | int, is_anonymized: bool):
     params = get_adjusted_parsing_params(year=year)
-    offset = get_parsing_offset(is_anonymized)
+    offset = get_parsing_offset(is_anonymized=is_anonymized)
     return convert_params_to_indices(params, offset)
 
 
diff --git a/parsing_utils.py b/parsing_utils.py
index e62471e..0989ee9 100644
--- a/parsing_utils.py
+++ b/parsing_utils.py
@@ -37,7 +37,7 @@ def parse_csv(fname: str, parsing_params):
     if not is_anonymized:
         text_data = remove_header(text_data)
 
-    return parse_text_data(text_data, parsing_params, is_anonymized)
+    return parse_text_data(text_data, parsing_params, is_anonymized=is_anonymized)
 
 
 def parse_text_data(
@@ -58,7 +58,7 @@ def parse_text_data(
 
         voter_name = read_voter_name(tokens, indices)
 
-        single_ballot = {}
+        single_ballot: dict = {}
         single_ballot = fill_in_review(tokens, indices, single_ballot=single_ballot)
         single_ballot = fill_in_game_list(
             tokens,
diff --git a/schulze_optional.py b/schulze_optional.py
index 6443e3a..922b350 100644
--- a/schulze_optional.py
+++ b/schulze_optional.py
@@ -12,21 +12,21 @@
 
 
 def apply_pipeline_for_optional_categories(
-    input_filename,
-    release_year="2020",
+    input_filename: str,
+    release_year: str = "2020",
     *,
-    try_to_break_ties=True,
-    use_igdb=True,
-    retrieve_igdb_data_from_scratch=True,
-    apply_hard_coded_extension_and_fixes=True,
-    use_levenshtein_distance=True,
-    goty_field="goty_preferences",
-    year_constraint="equality",
-    print_matches=True,
-    num_app_id_groups_to_display=3,
-    must_be_available_on_pc=False,
-    must_be_a_game=False,
-    verbose=False,
+    try_to_break_ties: bool = True,
+    use_igdb: bool = True,
+    retrieve_igdb_data_from_scratch: bool = True,
+    apply_hard_coded_extension_and_fixes: bool = True,
+    use_levenshtein_distance: bool = True,
+    goty_field: str = "goty_preferences",
+    year_constraint: str = "equality",
+    print_matches: bool = True,
+    num_app_id_groups_to_display: int = 3,
+    must_be_available_on_pc: bool = False,
+    must_be_a_game: bool = False,
+    verbose: bool = False,
 ) -> bool:
     ballots = load_ballots(input_filename)
 
diff --git a/tests.py b/tests.py
index 921340d..8c33bac 100644
--- a/tests.py
+++ b/tests.py
@@ -411,7 +411,7 @@ def test_filtering_out(self) -> None:
     def test_filter_out_votes_for_early_access_titles(self) -> None:
         ballot_year = "2018"
 
-        ballots = {}
+        ballots: dict = {}
 
         # Add dummy vote for an Early Access game
         ballots["dummy_voter_name"] = {}
@@ -810,7 +810,7 @@ def test_figure_out_ballots_with_missing_data(self) -> None:
         dummy_voter = "dummy_voter_name"
         goty_field = "dummy_preferences"
 
-        ballots = {}
+        ballots: dict = {}
         ballots[dummy_voter] = {}
         ballots[dummy_voter][goty_field] = {}
         ballots[dummy_voter][goty_field][1] = "Hello"
@@ -844,7 +844,7 @@ def test_figure_out_ballots_with_missing_data(self) -> None:
     def test_load_igdb_local_databases(self) -> None:
         ballot_year = "2018"
 
-        ballots = {}
+        ballots: dict = {}
 
         # Add dummy votes for the two actual GotY 2018 on MetaCouncil
         ballots["dummy_voter_name"] = {}
@@ -925,7 +925,7 @@ def test_load_igdb_match_database(self) -> None:
         assert data is not None
 
     def test_save_igdb_match_database(self) -> None:
-        data = {}
+        data: dict = {}
         file_name = "data/dummy_match_file_for_unit_test.json"
         igdb_databases.save_igdb_match_database(data, file_name=file_name)
         assert Path(file_name).exists()
@@ -936,7 +936,7 @@ def test_load_igdb_local_database(self) -> None:
         assert data is not None
 
     def test_save_igdb_local_database(self) -> None:
-        data = {}
+        data: dict = {}
         file_name = "data/dummy_local_file_for_unit_test.json"
         igdb_databases.save_igdb_local_database(data, file_name=file_name)
         assert Path(file_name).exists()