code: def update_objective(self, objective_form):
          
          # Implemented from template for
          # osid.resource.ResourceAdminSession.update_resource_template
          collection = JSONClientValidated('learning',
                                           collection='Objective',
                                           runtime=self._runtime)
          if not isinstance(objective_form, ABCObjectiveForm):
              raise errors.InvalidArgument('argument type is not an ObjectiveForm')
          if not objective_form.is_for_update():
              raise errors.InvalidArgument('the ObjectiveForm is for update only, not create')
          try:
              if self._forms[objective_form.get_id().get_identifier()] == UPDATED:
                  raise errors.IllegalState('objective_form already used in an update transaction')
          except KeyError:
              raise errors.Unsupported('objective_form did not originate from this session')
          if not objective_form.is_valid():
              raise errors.InvalidArgument('one or more of the form elements is invalid')
          collection.save(objective_form._my_map)
  
          self._forms[objective_form.get_id().get_identifier()] = UPDATED
  
          # Note: this is out of spec. The OSIDs don't require an object to be returned:
          return objects.Objective(
              osid_object_map=objective_form._my_map,
              runtime=self._runtime,
              proxy=self._proxy)
docs: Updates an existing objective.
  
          arg:    objective_form (osid.learning.ObjectiveForm): the form
                  containing the elements to be updated
          raise:  IllegalState - ``objective_form`` already used in an
                  update transaction
          raise:  InvalidArgument - the form contains an invalid value
          raise:  NullArgument - ``objective_form`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          raise:  Unsupported - ``objective_form`` did not originate from
                  ``get_objective_form_for_update()``
          *compliance: mandatory -- This method must be implemented.*