add operation analytic to invoice

invoice.py

@@ -0,0 +1,39 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+from trytond.pool import Pool, PoolMeta
+from trytond.model import ModelView, ModelSQL, fields
+from trytond.pyson import Eval
+
+from trytond.exceptions import UserError
+
+class Invoice(metaclass=PoolMeta):
+    'Account Invoice'
+    __name__ = 'account.invoice'
+
+    _states = {
+        'readonly': Eval('state') != 'draft',
+        }
+
+
+    account_analytic = fields.Many2One('analytic_account.account', 'Analytic Account', required=True,
+                                       domain=[('type', '=', 'normal')],
+                                       states=_states)
+
+    
+class InvoiceLine(metaclass=PoolMeta):
+      'Invoice Line'
+      __name__ = 'account.invoice.line'
+
+      @fields.depends('product', 'unit', '_parent_invoice.type', 'analytic_accounts',
+                      '_parent_invoice.party', 'party', 'invoice', 'invoice_type',
+                      '_parent_invoice.account_analytic', '_parent_invoice.invoice_date',
+                      '_parent_invoice.accounting_date','company', methods=['_get_tax_rule_pattern'])
+      def on_change_product(self):
+          super(InvoiceLine, self).on_change_product()
+          self.analytic_accounts = tuple()
+          try:
+              self.analytic_accounts += ({'root': self.invoice.account_analytic.root,
+                                          'account': self.invoice.account_analytic},) 
+          except:
+              pass
+