Issue #22769: Fixed ttk.Treeview.tag_has() when called without arguments.
diff --git a/Lib/lib-tk/ttk.py b/Lib/lib-tk/ttk.py
index 5ed018a..58f7698 100644
--- a/Lib/lib-tk/ttk.py
+++ b/Lib/lib-tk/ttk.py
@@ -1458,7 +1458,11 @@
         all items which have the specified tag.
 
         * Availability: Tk 8.6"""
-        return self.tk.getboolean(
+        if item is None:
+            return self.tk.splitlist(
+                self.tk.call(self._w, "tag", "has", tagname))
+        else:
+            return self.tk.getboolean(
                 self.tk.call(self._w, "tag", "has", tagname, item))