code: public function storeOutcomeVariable(RunnerServiceContext $context, $itemUri, $variableIdentifier, $variableValue)
      {
          $this->assertQtiRunnerServiceContext($context);
          $metaVariable = $this->getOutcomeVariable($variableIdentifier, $variableValue);
          return $this->storeVariable($context, $itemUri, $metaVariable);
      }
docs: Stores outcome variable related to an item, a test or a section
  
  @param RunnerServiceContext $context
  @param $itemUri
  @param $variableIdentifier
  @param $variableValue
  @return boolean
  @throws \common_Exception