clarify valid key types in print_stats method

Co-authored-by: Ege Akman <[email protected]>

Author: furkanonder

Doc/library/profile.rst

@@ -301,9 +301,12 @@ functions:
 
       The *sort* parameter specifies the sorting order of the displayed
       statistics. It accepts a single key or a tuple of keys to enable
-      multi-level sorting. A key can be either an integer, a string, or a
-      SortKey enum identifying the basis of a sort (for example: ``-1``,
-      ``'time'``, ``'name'``, ``SortKey.TIME``, or ``SortKey.NAME``).
+      multi-level sorting. When passing a tuple of keys, each key must be
+      either a string or a SortKey enum, excluding integers. However,
+      if only a single key is provided, it can be an integer, a string, or a
+      SortKey enum. These keys serve to identify the basis of the sort,
+      such as ``'time'``, ``'name'``, ``SortKey.TIME``, or ``SortKey.NAME``,
+      among others."
 
       .. versionadded:: 3.13
          :meth:`~Profile.print_stats` now accepts a single key or a tuple of keys.