def get_size_class(self, prefix='form-control'):
    if (self.size == 'small'):
        return (prefix + '-sm')
    if (self.size == 'large'):
        return (prefix + '-lg')
    return ''
def get_size_class(self, prefix='form-control'):
    if (self.size == 'small'):
        return (prefix + '-sm')
    if (self.size == 'large'):
        return (prefix + '-lg')
    return 