Refactor empty list check in tim_sort

Author: cclauss

sorts/tim_sort.py

@@ -55,9 +55,9 @@ def tim_sort(lst: list[Any] | tuple[Any, ...] | str) -> list[Any]:
     >>> tim_sort([])
     []
     """
-    length = len(lst)
-    if length == 0:
+    if not lst:
         return []
+    length = len(lst)
     runs, sorted_runs = [], []
     new_run = [lst[0]]
     sorted_array: list[Any] = []