Hi,

You can create a sequence like this,

first in XML:

<record id="seq_hr_employee" model="ir.sequence">
   <field name="name">omega_sequencer</field> 
   <field name="code">hr.employee</field>
   <field name="prefix">QO</field> 
   <field name="padding">5</field> 
</record>

Then in the python, override the create method and assign the value

@api.model
    def create(self, vals):
        seq = self.env['ir.sequence'].next_by_code('hr.employee') or '/'
        vals['sequence_id'] = seq
        return super(omega, self).create(vals)

Thanks