Tk button help

[Park997]

Hi,

I have a Tk button with a command (function) bound to it. The first
time the program is run, the command is executed without the button
being pushed. After this pushing the button does nothing.

Here is the relevant (I think) code. I would appreciate help in
understanding and fixing this:

	def run(self,G):
		
		from tkSimpleDialog import askfloat
	
		self.N = askfloat('N', 'Leaf N (50 - 250 mmol m-2) ')




if __name__ == '__main__':
	
	test = assimilation()
	
	import Gen_Graph
	
	from Tkinter import *

	top = Tk()
		
	G = Gen_Graph.grapher(top)

	Button(top, text='Enter Leaf N', command = test.run(G)).pack(side=RIGHT, fill
= BOTH)
	
	top.mainloop()  

Thanks.

Wendell Cropper