Subclassing Tkinter.Tcl
If you look inside Tcl function, you can see an interesting flag used to create Tk instance
def Tcl(screenName=None, baseName=None, className='Tk', useTk=0): return Tk(screenName, baseName, className, useTk)
Thus you can subclass Tk and inhibit Tk instantiation
class TclPlus(Tk): def __init__(self): Tk.__init__(self,useTk=0)tcl = TclPlus()tcl.eval("expr 6*7")