from odoo import fields, models WEEKDAY_SELECTION = [ ('1', 'Monday'), ('2', 'Tuesday'), ('3', 'Wednesday'), ('4', 'Thursday'), ('5', 'Friday'), ('6', 'Saturday'), ('7', 'Sunday'), ] class ResourceCalendar(models.Model): _inherit = 'resource.calendar' day_week_start = fields.Selection(WEEKDAY_SELECTION, string='Day Week Starts', required=True, default='1')