style: fix ruff problems

Author: RailtonDantas

src/dotenv/main.py

@@ -285,7 +285,6 @@ def unset_key(
 
     return removed, key_to_unset
 
-
 def resolve_variables(
     values: Iterable[Tuple[str, Optional[str]]],
     override: bool,
@@ -298,10 +297,11 @@ def resolve_variables(
     """
     new_values: Dict[str, Optional[str]] = {}
 
-    if override:
-        env = ChainMap(new_values, os.environ)  # type: ChainMap[str, Optional[str]]
-    else:
-        env = ChainMap(os.environ, new_values)  # type: ChainMap[str, Optional[str]]
+    env: ChainMap[str, Optional[str]] = (
+        ChainMap(new_values, os.environ)  # type: ignore
+        if override
+        else ChainMap(os.environ, new_values)  # type: ignore
+    )
 
     for name, value in values:
         if value is None:
@@ -314,7 +314,6 @@ def resolve_variables(
 
     return new_values
 
-
 def _walk_to_root(path: str) -> Iterator[str]:
     """
     Yield directories starting from the given directory up to the root