diff --git a/artipy/artifacts.py b/artipy/artifacts.py
index 44eca29..42333b0 100644
--- a/artipy/artifacts.py
+++ b/artipy/artifacts.py
@@ -2,9 +2,9 @@
 
 from __future__ import annotations
 
-from copy import deepcopy
 import random
 from collections.abc import Callable
+from copy import deepcopy
 from itertools import starmap
 
 from artipy import MAX_RARITY, UPGRADE_STEP
@@ -34,16 +34,19 @@ def _level_up_artifact(artifact: Artifact) -> None:
     artifact.level = new_level
     artifact.mainstat.set_value_by_level(new_level)
 
+
 def pick_stat(artifact: Artifact) -> SubStat:
     if not artifact.rarity:
-        raise ValueError("Artifact must have a rarity set")
-    
+        msg = "Artifact must have a rarity set"
+        raise ValueError(msg)
+
     stats = frozenset(s.name for s in (artifact.mainstat, *artifact.substats))
     pool = {s: w for s, w in substat_weights.items() if s not in stats}
-    
+
     if not pool:
-        raise ValueError("No valid stats available to pick from")
-        
+        msg = "No valid stats available to pick from"
+        raise ValueError(msg)
+
     population, weights = map(tuple, zip(*pool.items(), strict=False))
     new_stat_name = choose(population, weights)
     return create_substat(name=new_stat_name, rarity=artifact.rarity)
@@ -385,11 +388,11 @@ def with_rarity(self, rarity: int) -> ArtifactBuilder:
 
         self._artifact.rarity = rarity
         return self
-    
+
     @classmethod
     def five_star(cls) -> ArtifactBuilder:
         return cls().with_rarity(5)
-    
+
     @classmethod
     def four_star(cls) -> ArtifactBuilder:
         return cls().with_rarity(4)
diff --git a/artipy/data_gen.py b/artipy/data_gen.py
index f64db24..7051c30 100644
--- a/artipy/data_gen.py
+++ b/artipy/data_gen.py
@@ -1,11 +1,12 @@
 """Module that handles JSON data for the stats module."""
 
-import orjson
 import re
 from collections.abc import Iterator, Mapping, MutableMapping, Sequence
 from types import SimpleNamespace
 from typing import Any, ClassVar, cast
 
+import orjson
+
 from artipy import __data__
 
 
@@ -36,7 +37,7 @@ def recursive_namespace(data: Any) -> Any | SimpleNamespace:
         Any | SimpleNamespace: The converted data.
     """
     if isinstance(data, Mapping):
-        data = cast(Mapping[str, Any], data)
+        data = cast("Mapping[str, Any]", data)
         return SimpleNamespace(**{
             camel_to_snake_case(k): recursive_namespace(v) for k, v in data.items()
         })
@@ -86,7 +87,7 @@ def _load_data(self, file_name: str) -> None:
         with (__data__ / file_name).open("rb") as f:
             data = orjson.loads(f.read())
             if not hasattr(self, "_data"):
-                self._data = [recursive_namespace(item) for item in data]  # type: ignore
+                self._data = [recursive_namespace(item) for item in data]  # type: ignore[reportUninitializedInstanceVariable]
 
     def as_list(self) -> list[SimpleNamespace]:
         """Return the data as a list.
diff --git a/artipy/stats.py b/artipy/stats.py
index e83d374..b4bb6b2 100644
--- a/artipy/stats.py
+++ b/artipy/stats.py
@@ -58,6 +58,7 @@ def set_value_by_level(self, level: int) -> None:
         """Set the value of the mainstat based on the level of the artifact."""
         self.value = possible_mainstat_values(self.name, self.rarity)[level]
 
+
 @dataclass(slots=True)
 class SubStat(Stat):
     """Substat dataclass for a Genshin Impact artifact."""
diff --git a/artipy/utils.py b/artipy/utils.py
index 07c8c72..3b01e41 100644
--- a/artipy/utils.py
+++ b/artipy/utils.py
@@ -54,7 +54,7 @@ def possible_mainstat_values(stat: StatType, rarity: int) -> list[Decimal]:
         list[Decimal]: The possible values for the mainstat.
     """
     mainstat_data = MAINSTAT_DATA.as_list()
-    values = cast(list[StatContainer], mainstat_data[1:])
+    values = cast("list[StatContainer]", mainstat_data[1:])
     data = [
         j.value
         for i in values
@@ -77,7 +77,7 @@ def possible_substat_values(stat: StatType, rarity: int) -> list[Decimal]:
     Returns:
         list[Decimal]: The possible values for the substat.
     """
-    substat_data = cast(list[StatData], SUBSTAT_DATA.as_list())
+    substat_data = cast("list[StatData]", SUBSTAT_DATA.as_list())
     data = [
         d
         for d in substat_data