Hi, my question is about  how fill zeros at left in a field before save into BD...

my class:

class cliente(models.Model):

_inherit = 'res.partner'

Documento=fields.Selection((('V','V'),('E','E'),('J','J'),('P','P'),('G','G')),size=2, help="V=Venezolana , E= Extranjera , J= Juridico , P=Personal , G=Gubernamental", required=True)

cedula=fields.Char(size=11,default=None,string="Cedula De Identidad", help="acredita la identidad",required=True)

my views

<?xml version="1.0" encoding="UTF-8"?>

<openerp>

<data>

<record model="ir.ui.view" id="partner_form_view">

<field name="model">res.partner</field>

<field name="inherit_id" ref="base.view_partner_form"/>

<field name="arch" type="xml">

<group>

<field name="Documento"/>

<field name="cedula"/>

</group>

</field>

</record>

<!-- este es un acceso directo a la barra principal del menu-->

<menuitem id="menucontactos" name="Contactos"/>

<record model="ir.actions.act_window" id="contact_list_action">

<field name="name">Contactos de la Empresa</field>

<field name="res_model">res.partner</field>

<field name="view_mode">tree,form</field>

</record>

<menuitem id="configuration_menu" name="Configuraciones"

parent="menucontactos"/>

<menuitem id="contact_menu" name="Contacts"

parent="configuration_menu"

action="contact_list_action"/>

</data>

</openerp>

my idea is when press save button, fill zeros at left in a field cedula, Example:

anybody write 123 in field cedula:

cedula<= 123

then press save button

automatically 

cedula<=00000123

save into DB 00000123, not 123...

Thank you :D