i have created a manytoone field in contact module to enter multiple address for customer now i want to add the field in pos session partner screen.
how should i do that? 
this is my current code.

 res_partner_adddress.py

from odoo import models, fields, api
from odoo.exceptions import ValidationError
import re


class PartnerAddress(models.Model):
    _name = 'res.partner.address'
    _description = 'Partner Address'
    _sql_constraints = [
        ('unique_address_per_partner', 'UNIQUE(partner_id, address)', 'The address must be unique per partner.')
    ]

    partner_id = fields.Many2one('res.partner', string='Partner', required=True, ondelete='cascade')
    address = fields.Char(string='Address', required=True)
    phone_number = fields.Char(string='Phone Number', required=True)
    is_default = fields.Boolean(string='Is Default')

    @api.constrains('is_default')
    def _check_default_address(self):
        for record in self:
            if record.is_default:
                default_addresses = self.search([
                    ('partner_id', '=', record.partner_id.id),
                    ('is_default', '=', True),
                    ('id', '!=', record.id)
                ])
                if default_addresses:
                    raise ValidationError('A partner can have only one default address.')

    @api.constrains('phone_number')
    def _check_phone_number(self):
        for record in self:
            if not record.phone_number:
                raise ValidationError('Phone Number is required.')
            if not re.match(r'^\d+$', record.phone_number):
                raise ValidationError('Phone Number can contain only numbers.')


class ResPartner(models.Model):
    _inherit = 'res.partner'

    address_ids = fields.One2many('res.partner.address', 'partner_id', string='Addresses')