code: public function saveParameter($namespace, $name, $value)
      {
          $eventParams = ['namespace' => $namespace, 'name' => $name, 'value' => $value];
          $this->getEventManager()->trigger(__FUNCTION__, $this, $eventParams);
          if ($this->options->getCacheOptions()->isEnabled()) {
              $this->getCacheManager()->delete($namespace);
          }
          $parameter = $this->settingsMapper->findParameter($namespace, $name);
          if ($parameter) {
              if ($parameter->getValue() != $value) {
                  $parameter->setValue($value);
                  $this->getEventManager()->trigger('updateParameter', $this, ['parameter' => $parameter]);
                  $this->settingsMapper->updateParameter($parameter);
              }
          } else {
              $parameterEntityClass = $this->options->getParameterEntityClass();
              $parameter = new $parameterEntityClass;
              $parameter->setNamespace($namespace);
              $parameter->setName($name);
              $parameter->setValue($value);
              $this->getEventManager()->trigger('insertParameter', $this, ['parameter' => $parameter]);
              $this->settingsMapper->insertParameter($parameter);
          }
          $this->getEventManager()->trigger(__FUNCTION__ . '.post', $this, $eventParams);
      }
docs: {@inheritDoc}