I'v wrote the following program
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from Tkinter import *

class KeyDemo(Frame):
    """"""

    def __init__(self):
        """"""

        Frame.__init__(self)
        self.pack(expand=YES,fill=BOTH)
        self.master.title("Demonstrating Keystroke Events")
        self.master.geometry("350x100")

        self.message1=StringVar()
        self.line1=Label(self,textvariable=self.message1)
        self.message1.set("Type any key or shift")
        self.line1.pack()

        self.message2=StringVar()
        self.line2=Label(self,textvariable=self.message2)
        self.message2.set("")
        self.line2.pack()

        self.master.bind("<KeyPress>",self.keyPressed)
        self.master.bind("<KeyRelease>",self.keyReleased)

       
self.master.bind("<KeyPress-Shift_L>",self.shiftPressed)
       
self.master.bind("<KeyRelease-Shift_L>",self.shiftReleased)

    def keyPressed(self,event):
        """"""

        self.message1.set("Key pressed: "+ event.char)
        self.message2.set("This key is not left shift")

    def keyReleased(self,event):
        """"""

        self.message1.set("Key released: "+ event.char)
        self.message2.set("This key is not left shift")

    def shiftPressed(self,event):
        """"""

        self.message1.set("Shift pressed")
        self.message2.set("This key is left shift")

    def shiftReleased(self,event):
        """"""

        self.message1.set("Shift released")
        self.message2.set("This key is left shift")

def main():
    KeyDemo().mainloop()

if __name__=="__main__":
    main()

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When I pressed right shift , it shows:
 Key pressed:
This key is not left shift

And when I released right shift ,it shows:
Shift released
This key is left shift
But what I release is right shift.