Hi,

If you are looking to clear data entered in the one2many field and date field, you can try the below code,

@api.multi
def action_clear(self):
    for rec in self:
        rec.write({'order_line': [(5, 0, 0)],
                   'validity_date': ''})

Here in the above code, order_line is the One2many field and validity_date is the date field.

Thanks