Hello folks.
I have a model on my odoo that is populate by a XML when it is upgrade/installed.
I am trying to get the values of a column of this model to make a selection list into a form.

class ChargeRule(models.Model):
    """
    Class storing line item charge type lookup for Finance table logic .
    """
    _name = 'guimarc.linechargerule'
    line_type = fields.Char('line_type', required=True)
    loc = fields.Char('loc', required=True)
    prod_type = fields.Char('prod_type', required=True)
    cost_element = fields.Char('cost_element', required=True)

So I want create a form that  will have the field called cost element as well for the user be able to create a new entry.
However the entry only can be allowed with the names that are already stored into the guimarc.linechargerule.

1 - I have put this on the new model :
cost_element = fields.Many2one('ibmfinance.linechargerule',string='cost_element')

2 - On my form I have created like this : 
<form string="Fiance master cost" create="true" editable="top" delete="true">
   <sheet string="Finance Master Cost">
        <group>
            <group>
                <field name="cost_element"/>  ---- HERE 
                <field name="loc"/>
                <field name="cost"/>
                <field name="created_by"/>
                <field name="activate_date"/>
            </group>
        </group>
    </sheet>
</form
so when I open my form  it comes a drop LIST however with the IDS only like guimarc.linechargerule,1  guimarc.linechargerule,2 and etc.
 I would like to  see on the field the value of cost_element not the IDS.. the values of cost element.
Could you please help me on that? 
Thank you so much team