diff --git a/contract.py b/contract.py
index 91cfe9f..b65eeb9 100644
--- a/contract.py
+++ b/contract.py
@@ -69,30 +69,25 @@ class StaffContract(Workflow, ModelSQL, ModelView):
                     },
                 })
         cls._error_messages.update({
-                'employee_with_contract_current': ('The employee %s already has a contract '
-                'in draft or active!'),
-                'missing_contract_sequence': ('The contract sequence is '
-                'missing on configuration!'),
-                'finish_contract_out_date': ('You can not to finish a contract '
-                'with end date on future!'),
-                }
-        )
+            'employee_with_contract_current': ('The employee %s already has a contract in draft or active!'),
+            'missing_contract_sequence': ('The contract sequence is missing on configuration!'),
+            'finish_contract_out_date': ('You can not to finish a contract with end date on future!'),
+        })
 
     @classmethod
     def __register__(cls, module_name):
         super(StaffContract, cls).__register__(module_name)
-        TableHandler = backend.get('TableHandler')
         pool = Pool()
-        Identifier = pool.get('company.employee')
+        Employee = pool.get('company.employee')
         cursor = Transaction().connection.cursor()
         sql_table = cls.__table__()
-        identifier = Identifier.__table__()
+        employee = Employee.__table__()
 
         # Migration:
         # - Migration position from employee into contract
-        sub_query = identifier.select(
-            identifier.id, identifier.position,
-            where=(identifier.position != Null)
+        sub_query = employee.select(
+            employee.id, employee.position,
+            where=(employee.position != Null)
         )
         cursor.execute(*sub_query)