from odoo import api, fields, models class CRMLead(models.Model): _inherit = 'crm.lead' expense_total_amount = fields.Float(string='Expenses Total', compute='_compute_expense_total_amount', compute_sudo=True) expense_ids = fields.One2many('hr.expense', 'lead_id', string='Expenses') @api.multi @api.depends('expense_ids.total_amount') def _compute_expense_total_amount(self): for lead in self: lead.expense_total_amount = sum(lead.expense_ids.mapped('total_amount'))