dont duplicate records liquidation a payroll

exceptions.py

@@ -15,6 +15,9 @@ class LiquidationEmployeeError(UserError):
 class LiquidationDeleteError(UserError):
     pass
 
+class RecordDuplicateError(UserError):
+    pass
+
 
 class LiquidationMoveError(UserError):
     pass

liquidation.py

@@ -10,7 +10,8 @@ from trytond.transaction import Transaction
 from trytond.i18n import gettext
 from .exceptions import (
     LiquidationEmployeeError, MissingSecuenceLiquidation,
-    LiquidationMoveError, WageTypeConceptError, LiquidationDeleteError
+    LiquidationMoveError, WageTypeConceptError, LiquidationDeleteError,
+    RecordDuplicateError
 )
 
 STATES = {'readonly': (Eval('state') != 'draft')}
@@ -264,6 +265,10 @@ class Liquidation(Workflow, ModelSQL, ModelView):
             rec.set_liquidation_lines()
             cls.create_withholding(rec)
 
+    @classmethod
+    def copy(cls, records, default=None):
+        raise RecordDuplicateError(gettext('staff_payroll_co.msg_cannot_duplicate_record'))
+
     def get_dates(self, name):
         res = None
         if self.contract:

message.xml

@@ -65,5 +65,8 @@ this repository contains the full copyright notices and license terms. -->
         <record model="ir.message" id="msg_existing_move">
             <field name="text">Liquidation "%(liquidation)s" has a move, must be deleted before deletion.</field>
         </record>
+        <record model="ir.message" id="msg_cannot_duplicate_record">
+            <field name="text">You can't duplicate this record.</field>
+        </record>
     </data>
 </tryton>

payroll.py

@@ -20,7 +20,7 @@ from trytond.modules.staff_payroll.period import Period
 from trytond.modules.staff_payroll.payroll import PayrollReport, get_dom_contract_period
 from trytond.i18n import gettext
 from .exceptions import (GeneratePayrollError, MissingTemplateEmailPayroll,
-                         WageTypeConceptError)
+                         WageTypeConceptError, RecordDuplicateError)
 from .constants import (
     SHEET_FIELDS_NOT_AMOUNT, LIM_UVT_DEDUCTIBLE, ENTITY_ACCOUNTS,
     FIELDS_AMOUNT, EXTRAS, SHEET_SUMABLES, LIM_PERCENT_DEDUCTIBLE,
@@ -123,6 +123,10 @@ class Payroll(metaclass=PoolMeta):
         if self.employee and self.employee.department:
             self.department = self.employee.department.id
 
+    @classmethod
+    def copy(cls, records, default=None):
+        raise RecordDuplicateError(gettext('staff_payroll_co.msg_cannot_duplicate_record'))
+
     def create_move(self):
         super(Payroll, self).create_move()
         pool = Pool()