Hello everyone , I am using odoo 13.

In the HR  attendance module ,  employees in the system can check in and check out multiple times per day. I want to get the first check-in to the system for a specific employee per day. I have added new fields to hr.attendance so far, but I don't know what to do next.

class HrAttendance(models.Model):
    _inherit = 'hr.attendance'

    first_sign_in = fields.Datetime(string="First Check In", readonly="1")