[web2py] IS_IN_SET inside INPUT

[CesarBustios]

Hi, im trying to use the IS_IN_SET requirement in a form, i'm using:

form = FORM('Campaña ',
              INPUT(_type='text', _name='name',
requires=IS_IN_SET(['A', 'B', 'C'])),
              INPUT(_type='submit'))

I'm not sure this is the right code, can you help me out please?

Thanks!