TYP: make sure _names is indexed with an int

Author: iasoon

pandas/core/frame.py

@@ -10370,12 +10370,14 @@ def _count_level(self, level: Level, axis: int = 0, numeric_only: bool = False):
         else:
             mask = index_mask.reshape(-1, 1) & values_mask
 
-        if isinstance(level, str):
-            level = count_axis._get_level_number(level)
+        if isinstance(level, int):
+            level_number = level
+        else:
+            level_number = count_axis._get_level_number(level)
 
-        level_name = count_axis._names[level]
-        level_index = count_axis.levels[level]._rename(name=level_name)
-        level_codes = ensure_platform_int(count_axis.codes[level])
+        level_name = count_axis._names[level_number]
+        level_index = count_axis.levels[level_number]._rename(name=level_name)
+        level_codes = ensure_platform_int(count_axis.codes[level_number])
         counts = lib.count_level_2d(mask, level_codes, len(level_index), axis=axis)
 
         if axis == 1: