I write query but don't get data from database , here this def _compute_amount function calculate total field and store data after that i need summation of total field data retrieve to cash field .

How i can i solve this kindly help me

.py file

from odoo import api, models, fields


class CashinBalance(models.Model):
    _name = 'cashinbalance.cashinbalance'
    _description = 'Cash-in Balance'

    atk = fields.Integer('TK.1000')
    btk = fields.Integer('TK.500')
    ctk = fields.Integer('TK.100')
    dtk = fields.Integer('TK.50')
    etk = fields.Integer('TK.20')
    ftk = fields.Integer('TK.10')
    gtk = fields.Integer('TK.5')
    htk = fields.Integer('TK.2')
    date = fields.Date(required=True, default=fields.Date.context_today)
    total = fields.Integer('Total Cash-In Balance', compute='_compute_amount', store=True)
    cash = fields.Integer(compute='get_data', store=True)

    @api.depends('atk', 'btk', 'ctk', 'dtk', 'etk', 'ftk', 'gtk', 'htk')
    def _compute_amount(self):
        for expense in self:
            expense.total = expense.atk * 1000 + expense.btk * 500 + expense.ctk * 100 + expense.dtk * 50 \
                            + expense.etk * 20 + expense.ftk * 10 + expense.gtk * 5 + expense.htk * 2

    def get_data(self):
        for rec in self:
            self._cr.execute("""SELECT SUM(total) from cashinbalance_cashinbalance""")
            data = self._cr.dictfetchall()
            rec.cash = data[0]['sum']


.xml
<?xml version="1.0" encoding="UTF-8" ?>
<odoo>
    <!--   Tree view      -->
    <record id="cashin_tree_view" model="ir.ui.view">
         <field name="name">cashin.tree.view</field>
         <field name="model">cashinbalance.cashinbalance</field>
         <field name="arch" type="xml">
            <tree string="Cash">
                                <field name="atk"/>
                        <field name="btk"/>
                        <field name="ctk"/>
                        <field name="dtk"/>
                        <field name="etk"/>
                        <field name="ftk"/>
                        <field name="gtk"/>
                        <field name="htk"/>
                                <field name="date"/>
                        <field name="cash"/>
            </tree>
         </field>
      </record>
<!-- End Tree View   -->

    <!-- Form View for  -->
      <record id="cashin_form_view" model="ir.ui.view">
         <field name="name">cashin.form.view</field>
         <field name="model">cashinbalance.cashinbalance</field>
         <field name="arch" type="xml">
            <form>
               <sheet>
                  <group style="text-align:center" string="Yuko Leather Goods Ltd.">
                  </group>
                  <group style="text-align:center" string="Cash-In Details">
                  </group>

                  <group>
                  <group string="Tk-Quantity">
                  </group>
                  </group>

                  <group>
                     <group>
                                <field name="atk"/>
                                <br/>
                        <field name="btk"/>
                                 <br/>
                        <field name="ctk"/>
                                 <br/>
                        <field name="dtk"/>
                                 <br/>
                        <field name="etk"/>
                                 <br/>
                        <field name="ftk"/>
                                 <br/>
                        <field name="gtk"/>
                                 <br/>
                        <field name="htk"/>
                                 <br/>
                                <field name="date"/>
                                 <br/>
                     </group>
                            <group>
                                <field name="cash"/>
                            </group>
                      </group>
               </sheet>
            </form>
         </field>
      </record>


   <record id="action_cashin" model="ir.actions.act_window" >
      <field name="name"> Cash </field>
      <field name="type">ir.actions.act_window</field>
      <field name="res_model">cashinbalance.cashinbalance</field>
<!--      <field name="view_type">form</field>-->
      <field name="view_mode">tree,form</field>
   </record>

   <menuitem id="Cash_root" name="Cash Balance Monitoring" sequence="1" />
   <menuitem id="cash_in" name="Cash-In" parent="Cash_root" action="action_cashin"/>
</odoo>