Q:

Syntax-error: Non keyword-arg after keyword arg - OpenErp

I got this error
Client Traceback (most recent call last):
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\web\http.py", line 203, in dispatch
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\web\controllers\main.py", line 1410, in load
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\web\session.py", line 43, in proxy
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\web\session.py", line 31, in proxy_method
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\web\session.py", line 104, in send

Server Traceback (most recent call last):
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\web\session.py", line 90, in send
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\netsvc.py", line 293, in dispatch_rpc
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\service\web_services.py", line 622, in dispatch
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\service\security.py", line 40, in check
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\pooler.py", line 49, in get_pool
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\pooler.py", line 33, in get_db_and_pool
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\modules\registry.py", line 192, in get
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\modules\registry.py", line 218, in new
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\modules\loading.py", line 344, in load_modules
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\modules\loading.py", line 259, in load_marked_modules
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\modules\loading.py", line 162, in load_module_graph
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\modules\module.py", line 405, in load_openerp_module
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\.\openerp\modules\module.py", line 133, in load_module
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\certificados\__init__.py", line 1, in <module>
File "C:\Program Files\OpenERP 7.0-20130321-002353\Server\server\openerp\addons\certificados\certificados.py", line 37
'Valor_En_Divisas' : fields.function(multi_a_b, type='integer', 'Valor En Divisas'),
SyntaxError: non-keyword arg after keyword arg

And this is the code in my module.py
 _columns = {
    'Codigo_Arancelario' : fields.integer('Codigo Arancelario'),
    'product_id' : fields.many2one('product.product', 'Material'),
    'Descripcion_Arancelaria' : fields.char('Descripcion Arancelaria', size=42, required = True, translate = True), 
    'Especificaciones_Tecnicas' : fields.char('Especificaciones Tecnicas', size=60, required = True, translate = True), 
    'Cantidad' : fields.float('Cantidad'), 'Unidad_de_Medida': fields.many2one('product.uom', 'Unidad de Medida'),
    'Precio_Unitario_Declarado' : fields.float('Precio Unitario Declarado'), 'Moneda' : fields.many2one('res.currency', 'Moneda'),
    'Valor_En_Divisas' : fields.function(multi_a_b, type='integer', 'Valor En Divisas'),
    'requisicion_id' : fields.many2one('certificados.certificados', 'Certificados de No Produccion', ondelete='cascade'),
    'Cantidad_Consumida' : fields.float('Cantidad Consumida'), 'Cantidad_Disponible' : fields.float('Cantidad Disponible'),

}

Being "Valor_En_Divisas" the error syntax, but i don't know what is exactly giving me this error? 
Any help would be greatly appreciated.

A:

You have a non-keyword argument:
fields.function(multi_a_b, type='integer', 'Valor En Divisas'),
                                           ^^^^^^^^^^^^^^^^^^

After a keyword argument:
fields.function(multi_a_b, type='integer', 'Valor En Divisas'),
                           ^^^^^^^^^^^^^^

To fix it, make that last one a keyword argument:
fields.function(multi_a_b, type='integer', string='Valor En Divisas'),

