@validate('form')
def valid_type_in_col(arch):
 return all((attrib.isdigit() for attrib in arch.xpath('//@col')))

@ validate ( 'form' ) def valid_type_in_col ( arch ) : return all ( ( attrib . isdigit ( ) for attrib in arch . xpath ( '//@col' ) ) )
a col attribute must be an integer type .