Step-1 Install base report module.

Step-2 After that customize base report module.

In below example, I have customised base report module. You can directly use the below base report module in your addons and run in Odoo server.

    def onchange_reconcile(self, cr, uid, ids, reconcile, amount, amount_unreconciled, context=None): 
        vals = {'amount': 0.0} 
        if reconcile: 
            vals = { 'amount': amount_unreconciled} 
        return {'value': vals} 

    def onchange_amount(self, cr, uid, ids, amount, amount_unreconciled, context=None): 
        vals = {} 
        if amount: 
            vals['reconcile'] = (amount == amount_unreconciled) 
        return {'value': vals} 

    def onchange_move_line_id(self, cr, user, ids, move_line_id, context=None): 
        """