import maya.cmds as cmds
global tmp
cmds.window( width=150 )
cmds.columnLayout( adjustableColumn=True )
cmds.button( label='Button 1' ,command="tmp = 'test1'")
cmds.button( label='Button 2' ,command="tmp = 'test2'")
cmds.button( label='Button 3' ,command="tmp = 'test3'")
cmds.button( label='Button 4' ,command="tmp = 'test4'")
cmds.showWindow()
print tmp