for string in {'update', 'add', 'check', 'mirror', 'fill_sink', 'textarea', 'table', 'move_up', 'move_down', 'add_taxes', 'replace'}:
if string in postvars.keys():
submit_button = string
break
for string in {'update', 'add', 'check', 'mirror', 'fill_sink', 'textarea', 'table', 'move_up', 'move_down', 'add_taxes', 'replace'}:
if string in postvars.keys():
submit_button = string
break