code: public function load($className, $forceReload = false)
      {
          $this->typeCheck->load(func_get_args());
  
          // Extension is already loaded ...
          if (!$forceReload && $this->isLoaded($className)) {
              return $this->extensions[$className];
          }
  
          // Obtain a reflector ...
          try {
              $reflector = new ReflectionClass($className);
          } catch (ReflectionException $e) {
              throw new Exception\InvalidExtensionException($className, $e);
          }
  
          // Verify interface ...
          if (!$reflector->implementsInterface('Eloquent\Typhoon\Extension\ExtensionInterface')) {
              throw new Exception\InvalidExtensionException($className);
          }
  
          return $this->extensions[$className] = $reflector->newInstanceArgs($this->constructorArguments);
      }
docs: @param string  $className   The name of the extension class.
  @param boolean $forceReload
  
  @return ExtensionInterface