reading a field value from another model odoo13

Question

what i'm trying to do here is creating a new field dimension that gets value from a field in the [stock.move] model this approach doesn't work i don't know why and it's not getting any errors from the python file the only error from the xpath tag at the xml file

this is models.py file

xx_Custom_Invoice(models.Model):
    _inherit = 'account.move'
    dimension = fields.Char(String="XxX", compute='get_data')

    def get_data(self):
       stock_move = self.env['stock.move']
       for move in self:
          picking = stock_move.picking_id
          if move.id != picking.account_move_ids:
              continue
          for line in move:
              line.update({
                'dimension': line.dimension,
              })  

here is the views.xml

 <record id="xx_account_move_view_inherit" model="ir.ui.view" >
<field name="name">account.move.view.inherit</field>
<field name="model">account.move</field>
<field name="inherit_id" ref="account.view_move_form"/>
<field name="arch" type="xml">
    <xpath expr="/form/sheet/notebook/page/field[@name='invoice_line_ids']/tree/field[@name='product_id']" position="after">
        <field name="dimension"/>
    </xpath>
  </field>
 </record>

Answer 1

There is an issue here:

       stock_move = self.env['stock.move']
       for move in self:

stock_move here is an empty recordset, so no iteration will happen in the for loop. You probably to use search() to fetch the record you want to operate on:

       stock_move = self.env['stock.move'].search(<DOMAIN>)
       for move in self: