I have customizing a module in odoo 8 .But When I create invoices I got below error .How to override amount_all method in odoo 8

additional_discount/invoice.py", line 19, in _amount_all

return self._amount_all_generic(account_invoice, *args, **kwargs)

File "/home/ubuntu-libu/odoo/addons/additional_discount/common.py", line 27, in _amount_all_generic

res = super(cls, self)._amount_all(cr, uid, ids, field_name, arg, context)

AttributeError: 'super' object has no attribute '_amount_all'

This is my  Full code-----------------------------------------------------

================

.xml-------------------

<?xml version="1.0" encoding="UTF-8"?>

<openerp>

<data>

<record id="view_order_additional_discount" model="ir.ui.view">

<field name="name">sale.order.form</field>

<field name="model">sale.order</field>

<field name="type">form</field>

<field name="inherit_id" ref="sale.view_order_form"/>

<field name="arch" type="xml">

<field name="amount_untaxed" position="after">

<field name="add_disc" colspan="2"/>

<!-- <field name="add_disc_amt" colspan="2"/> -->

<field name="amount_net" sum="Net Amount" colspan="2"/>

</field>

</field>

</record>

<record id="purchase_order_form_add_discount" model="ir.ui.view">

<field name="name">purchase.order.form</field>

<field name="model">purchase.order</field>

<field name="type">form</field>

<field name="inherit_id" ref="purchase.purchase_order_form"/>

<field name="arch" type="xml">

<field name="amount_untaxed" position="after">

<field name="add_disc" colspan="2"/>

<!-- <field name="add_disc_amt" colspan="2"/> -->

<field name="amount_net" sum="Net Amount" colspan="2"/>

</field>

</field>

</record>

<record id="invoice_form_add_discount" model="ir.ui.view">

<field name="name">account.invoice.form</field>

<field name="model">account.invoice</field>

<field name="type">form</field>

<field name="inherit_id" ref="account.invoice_form"/>

<field name="arch" type="xml">

<field name="amount_untaxed" position="after">

<field name="add_disc" />

<!-- <field name="add_disc_amt" /> -->

<field name="amount_net" sum="Net Amount"/>

</field>

</field>

</record>

<record id="invoice_supplier_form_add_discount" model="ir.ui.view">

<field name="name">account.invoice.supplier.form</field>

<field name="model">account.invoice</field>

<field name="type">form</field>

<field name="inherit_id" ref="account.invoice_supplier_form"/>

<field name="priority">2</field>

<field name="arch" type="xml">

<field name="amount_untaxed" position="after">

<field name="add_disc" />

<!-- <field name="add_disc_amt" /> -->

<field name="amount_net" sum="Net Amount"/>

</field>

</field>

</record>

</data>

</openerp>

===================

************init.py**************

import sale

import purchase

import invoice

===========================================================

*************common.py  ***********

from osv import osv

from tools.translate import _

class AdditionalDiscountable(object):

    _line_column = 'order_line'

    _tax_column = 'tax_id'

    def record_currency(self, record):

        """Return currency browse record from a browse record.

        Default implementation is for sale/purchase order.

        """

        return record.pricelist_id.currency_id

    def _amount_all_generic(self, cls, cr, uid, ids, field_name, arg,

                            context=None):

        """Generic overload of the base method to add discount infos

        This is a generic version that needs to be passed the caller class (for

        super).

        For now it can be applied to sale.order, purchase.order and

        account.invoice, using the methods and attrs of AdditionalDiscountable

        """

        cur_obj = self.pool.get('res.currency')

        res = super(cls, self)._amount_all(cr, uid, ids, field_name, arg, context)

        for record in self.browse(cr, uid, ids, context=context):

            # Taxes are applied line by line, we cannot apply a

            # discount on taxes that are not proportional

            if not all(t.type == 'percent'

                       for line in getattr(record, self._line_column)

                       for t in getattr(line, self._tax_column)):

                raise osv.except_osv(_('Discount error'),

                                     _('Unable (for now) to compute a global '

                                       'discount with non percent-type taxes'))

            o_res = res[record.id]

            cur = self.record_currency(record)

            def cur_round(value):

                """Round value according to currency."""

                return cur_obj.round(cr, uid, cur, value)

            # add discount

            amount_untaxed = sum(line.price_subtotal

                                 for line in getattr(record, self._line_column))

            add_disc = record.add_disc

            add_disc_amt = cur_round(amount_untaxed * add_disc / 100)

            o_res['add_disc_amt'] = add_disc_amt

            o_res['amount_net'] = o_res['amount_untaxed'] - add_disc_amt

            # we apply a discount on the tax as well.

            # We might have rounding issue

            o_res['amount_tax'] = cur_round(

                o_res['amount_tax'] * (100.0 - (add_disc or 0.0))/100.0)

            o_res['amount_total'] = o_res['amount_net'] + o_res['amount_tax']

        return res

====================

****************invoice.py*************

import openerp.addons.decimal_precision as dp

from openerp.osv import fields, osv

from common import AdditionalDiscountable

from openerp.tools.translate import _

class account_invoice(AdditionalDiscountable, osv.Model):

_inherit = "account.invoice"

_description = 'Invoice'

_line_column = 'invoice_line'

_tax_column = 'invoice_line_tax_id'

def record_currency(self, record):

"""Return currency browse record from an invoice record (override)."""

return record.currency_id

def _amount_all(self, *args, **kwargs):

return self._amount_all_generic(account_invoice, *args, **kwargs)

def _get_invoice_line(self, cr, uid, ids, context=None):

"""copy pasted from account_invoice"""

result = {}

for line in self.pool.get('account.invoice.line').browse(cr, uid, ids, context=context):

result[line.invoice_id.id] = True

return result.keys()

def _get_invoice_tax(self, cr, uid, ids, context=None):

"""copy pasted from account_invoice"""

result = {}

for tax in self.pool.get('account.invoice.tax').browse(cr, uid, ids, context=context):

result[tax.invoice_id.id] = True

return result.keys()

_columns={

'add_disc':fields.float('Additional Discount(-)',digits=(4,2),readonly=True, states={'draft':[('readonly',False)]}),

'add_disc_amt': fields.function(_amount_all, method=True, digits_compute= dp.get_precision('Sale Price'), string='Additional Disc Amt',

store =True,multi='sums', help="The additional discount on untaxed amount."),

'amount_net': fields.function(_amount_all, method=True, digits_compute= dp.get_precision('Sale Price'), string='Net Amount',

store = True,multi='sums', help="The amount after additional discount."),

'amount_untaxed': fields.function(_amount_all, digits_compute=dp.get_precision('Account'), string='Untaxed',

store={

'account.invoice': (lambda self, cr, uid, ids, c={}: ids, ['invoice_line', 'add_disc'], 20),

'account.invoice.tax': (_get_invoice_tax, None, 20),

'account.invoice.line': (_get_invoice_line, ['price_unit','invoice_line_tax_id','quantity','discount','invoice_id'], 20),

},

multi='all'),

'amount_tax': fields.function(_amount_all, digits_compute=dp.get_precision('Account'), string='Tax',

store={

'account.invoice': (lambda self, cr, uid, ids, c={}: ids, ['invoice_line', 'add_disc'], 20),

'account.invoice.tax': (_get_invoice_tax, None, 20),

'account.invoice.line': (_get_invoice_line, ['price_unit','invoice_line_tax_id','quantity','discount','invoice_id'], 20),

},

multi='all'),

'amount_total': fields.function(_amount_all, digits_compute=dp.get_precision('Account'), string='Total',

store={

'account.invoice': (lambda self, cr, uid, ids, c={}: ids, ['invoice_line', 'add_disc'], 20),

'account.invoice.tax': (_get_invoice_tax, None, 20),

'account.invoice.line': (_get_invoice_line, ['price_unit','invoice_line_tax_id','quantity','discount','invoice_id'], 20),

},

multi='all'),

}

_defaults={

'add_disc': 0.0,

}

class account_invoice_tax(osv.Model):

_inherit = 'account.invoice.tax'

def compute(self, cr, uid, invoice_id, context=None):

tax_grouped = super(account_invoice_tax, self).compute(cr, uid, invoice_id, context)

tax_pool = self.pool.get('account.tax')

cur_pool = self.pool.get('res.currency')

tax_ids = set([key[0] for key in tax_grouped])

taxes = tax_pool.browse(cr, uid, tax_ids)

if taxes and not all(t.type == 'percent' for t in taxes):

raise osv.except_osv(_('Discount error'),

_('Unable (for now) to compute a global '

'discount with non percent-type taxes'))

invoice = self.pool.get('account.invoice').browse(cr, uid, invoice_id, context=context)

add_disc = invoice.add_disc

cur = invoice.currency_id

for line in tax_grouped:

for key in ('tax_amount', 'base_amount', 'amount', 'base'): #FIXME?

val = tax_grouped[line][key]

tax_grouped[line][key] = cur_pool.round(cr, uid, cur, val * (1.0 - add_disc / 100.0))

print tax_grouped

return tax_grouped

============================

********************purchase.py**********

from openerp.osv import osv, fields

import openerp.addons.decimal_precision as dp

from openerp.tools.translate import _

from common import AdditionalDiscountable

class purchase_order(AdditionalDiscountable, osv.osv):

_inherit = "purchase.order"

_description = "Purchase Order"

_tax_column = 'taxes_id'

_line_column = 'order_line'

def _amount_all(self, *args, **kwargs):

return self._amount_all_generic(purchase_order, *args, **kwargs)

_columns={

'add_disc': fields.float('Additional Discount(-)', digits=(4,2),

states={'confirmed': [('readonly',True)],

'approved': [('readonly',True)],

'done': [('readonly',True)]}),

'add_disc_amt': fields.function(_amount_all, method=True, store=True, multi='sums',

digits_compute= dp.get_precision('Sale Price'),

string='Additional Disc Amt',

help="The additional discount on untaxed amount."),

'amount_net': fields.function(_amount_all, method=True, store=True, multi='sums',

digits_compute= dp.get_precision('Sale Price'),

string='Net Amount',

help="The amount after additional discount."),

'amount_untaxed': fields.function(_amount_all, method=True, store=True, multi="sums",

digits_compute= dp.get_precision('Purchase Price'),

string='Untaxed Amount',

help="The amount without tax"),

'amount_tax': fields.function(_amount_all, method=True, store=True, multi="sums",

digits_compute= dp.get_precision('Purchase Price'),

string='Taxes',

help="The tax amount"),

'amount_total': fields.function(_amount_all, method=True, store=True, multi="sums",

digits_compute= dp.get_precision('Purchase Price'),

string='Total',

help="The total amount"),

}

_defaults={

'add_disc': 0.0,

}

def action_invoice_create(self, cr, uid, ids, context=None):

"""Add a discount in the invoice after creation, and recompute the total

"""

inv_obj = self.pool.get('account.invoice')

for order in self.browse(cr, uid, ids, context):

# create the invoice

inv_id = super(purchase_order, self).action_invoice_create(cr, uid, ids, context)

# modify the invoice

inv_obj.write(cr, uid, [inv_id], {'add_disc': order.add_disc or 0.0}, context)

inv_obj.button_compute(cr, uid, [inv_id], context=context, set_total=True)

res = inv_id

return res

********sale.py*****************

from openerp.osv import fields, osv

import openerp.addons.decimal_precision as dp

from openerp.tools.translate import _

from common import AdditionalDiscountable

class sale_order(AdditionalDiscountable, osv.osv):

_inherit = 'sale.order'

_tax_column = 'tax_id'

_line_column = 'order_line'

def _amount_all(self, *args, **kwargs):

return self._amount_all_generic(sale_order, *args, **kwargs)

_columns = {

'add_disc':fields.float('Additional Discount(-)',digits=(4,2), readonly=True, states={'draft': [('readonly', False)]}),

'add_disc_amt': fields.function(_amount_all, method=True, digits_compute= dp.get_precision('Sale Price'), string='Additional Disc Amt',

store =True,multi='sums', help="The additional discount on untaxed amount."),

'amount_untaxed': fields.function(_amount_all, method=True, digits_compute= dp.get_precision('Sale Price'), string='Untaxed Amount',

store = True,multi='sums', help="The amount without tax."),

'amount_net': fields.function(_amount_all, method=True, digits_compute= dp.get_precision('Sale Price'), string='Net Amount',

store = True,multi='sums', help="The amount after additional discount."),

'amount_tax': fields.function(_amount_all, method=True, digits_compute= dp.get_precision('Sale Price'), string='Taxes',

store = True,multi='sums', help="The tax amount."),

'amount_total': fields.function(_amount_all, method=True, digits_compute= dp.get_precision('Sale Price'), string='Total',

store = True,multi='sums', help="The total amount."),

}

_defaults={

'add_disc': 0.0,

}

def _make_invoice(self, cr, uid, order, lines, context=None):

"""Add a discount in the invoice after creation, and recompute the total

"""

inv_obj = self.pool.get('account.invoice')

# create the invoice

inv_id = super(sale_order, self)._make_invoice(cr, uid, order, lines, context)

# modify the invoice

inv_obj.write(cr, uid, [inv_id], {'add_disc': order.add_disc or 0.0}, context)

inv_obj.button_compute(cr, uid, [inv_id])

return inv_id