Function help

I can't get a function called by pressing a key. Here's a quick example of what i'm talking about:

Graphics 800, 600

While Not KeyHit(1)

	If KeyDown(156)=True Then dothis(a$) ;enter key
	
	Flip
	
Wend
End

Function dothis(a$)

a$ = "asd"

Print a$

End Function

How do you call functions by pressing a key? My code above doesn't work..

	If KeyDown(156)=True Then dothis(a$) ;enter key

should read

	If KeyDown(156)=True Then dothis(a$) ;numpad enter key

OH, my bad! Hehe, thanks man.