constrain partner domain to cooperatives

models/crm.py

@@ -7,6 +7,8 @@ from odoo import fields, models
 class Lead(models.Model):
     _inherit = "crm.lead"
 
+    partner_id = fields.Many2one(domain=[("is_cooperative", "=", True)])
+
     mucs_type = fields.Selection(
         selection=[
             ('proposition', 'Proposition'),