Close a specific window(frame) in opencv2. Using python

I have this kind of code at the end of my whole code . This is the command to close the window when i click on letter 'e'

if   cv2.waitKey(0) & 0xFF == ord("e") :
     cv2.destroyWindow('Train Device')
break   

I just want to close only a specific window when i am clicking on the letter (e) but when i use this one it close everything all the frames and not only the specific one. 'Train Device' is name of my window. When am i doing wrong?