Issue #15133: _tkinter.tkapp.getboolean() now supports long and Tcl_Obj and
always returns bool.  tkinter.BooleanVar now validates input values (accepted
bool, int, long, str, unicode, and Tcl_Obj).  tkinter.BooleanVar.get() now
always returns bool.
diff --git a/Lib/lib-tk/Tkinter.py b/Lib/lib-tk/Tkinter.py
index 8d21717..cb7edf0 100644
--- a/Lib/lib-tk/Tkinter.py
+++ b/Lib/lib-tk/Tkinter.py
@@ -401,6 +401,10 @@
         """
         Variable.__init__(self, master, value, name)
 
+    def set(self, value):
+        """Set the variable to VALUE."""
+        return self._tk.globalsetvar(self._name, self._tk.getboolean(value))
+
     def get(self):
         """Return the value of the variable as a bool."""
         return self._tk.getboolean(self._tk.globalgetvar(self._name))