null, $share = false)
    {
        unset($this->shared[$alias]);
        unset($this->definitions[$alias]);
        unset($this->sharedDefinitions[$alias]);

        if (is_null($concrete)) {
            $concrete = $alias;
        }

        $definition = $this->definitionFactory->getDefinition($alias, $concrete);

        if ($definition instanceof DefinitionInterface) {
            if ($share === false) {
                $this->definitions[$alias] = $definition;
            } else {
                $this->sharedDefinitions[$alias] = $definition;
            }

            return $definition;
        }

        // dealing with a value that cannot build a definition
        $this->shared[$alias] = $concrete;
    }

    /**
     * {@inheritdoc}
     */
    public function share($alias, $concrete = null)
    {
        return $this->add($alias, $concrete, true);
    }

    /**
     * {@inheritdoc}
     */
    public function addServiceProvider($provider)
    {
        $this->providers->add($provider);

        return $this;
    }

    /**
     * {@inheritdoc}
     */
    public function extend($alias)
    {
        if ($this->providers->provides($alias)) {
            $this->providers->register($alias);
        }

        if (array_key_exists($alias, $this->definitions)) {
            return $this->definitions[$alias];
        }

        if (array_key_exists($alias, $this->sharedDefinitions)) {
            return $this->sharedDefinitions[$alias];
        }

        throw new NotFoundException(
            sprintf('Unable to extend alias (%s) as it is not being managed as a definition', $alias)
        );
    }

    /**
     * {@inheritdoc}
     */
    public function inflector($type, callable $callback = null)
    {
        return $this->inflectors->add($type, $callback);
    }

    /**
     * {@inheritdoc}
     */
    public function call(callable $callable, array $args = [])
    {
        return (new ReflectionContainer)->setContainer($this)->call($callable, $args);
    }

    /**
     * Delegate a backup container to be checked for services if it
     * cannot be resolved via this container.
     *
     * @param  \Interop\Container\ContainerInterface $container
     * @return $this
     */
    public function delegate(InteropContainerInterface $container)
    {
        $this->delegates[] = $container;

        if ($container instanceof ImmutableContainerAwareInterface) {
            $container->setContainer($this);
        }

        return $this;
    }

    /**
     * Returns true if service is registered in one of the delegated backup containers.
     *
     * @param  string $alias
     * @return boolean
     */
    public function hasInDelegate($alias)
    {
        foreach ($this->delegates as $container) {
            if ($container->has($alias)) {
                return true;
            }
        }

        return false;
    }

    /**
     * Attempt to get a service from the stack of delegated backup containers.
     *
     * @param  string $alias
     * @param  array  $args
     * @return mixed
     */
    protected function getFromDelegate($alias, array $args = [])
    {
        foreach ($this->delegates as $container) {
            if ($container->has($alias)) {
                return $container->get($alias, $args);
            }

            continue;
        }

        throw new NotFoundException(
            sprintf('Alias (%s) is not being managed by the container', $alias)
        );

    }

    /**
     * Get a service that has been registered in this container.
     *
     * @param  string $alias
     * @param  array $args
     * @return mixed
     */
    protected function getFromThisContainer($alias, array $args = [])
    {
        if ($this->hasShared($alias, true)) {
            $shared = $this->inflectors->inflect($this->shared[$alias]);
            if ($shared instanceof RawArgumentInterface) {
                return $shared->getValue();
            }
            return $shared;
        }

        if (array_key_exists($alias, $this->sharedDefinitions)) {
            $shared = $this->inflectors->inflect($this->sharedDefinitions[$alias]->build());
            $this->shared[$alias] = $shared;
            return $shared;
        }

        if (array_key_exists($alias, $this->definitions)) {
            return $this->inflectors->inflect(
                $this->definitions[$alias]->build($args)
            );
        }

        throw new NotFoundException(
            sprintf('Alias (%s) is not being managed by the container', $alias)
        );
    }
}
<br />
<b>Fatal error</b>:  Uncaught Error: Class 'League\Container\Container' not found in /home/payon/public_html/wp-content/plugins/wp-rocket/inc/classes/class-plugin.php:32
Stack trace:
#0 /home/payon/public_html/wp-content/plugins/wp-rocket/inc/main.php(39): WP_Rocket\Plugin-&gt;__construct('/home/payon/pub...')
#1 /home/payon/public_html/wp-includes/class-wp-hook.php(308): rocket_init('')
#2 /home/payon/public_html/wp-includes/class-wp-hook.php(332): WP_Hook-&gt;apply_filters(NULL, Array)
#3 /home/payon/public_html/wp-includes/plugin.php(517): WP_Hook-&gt;do_action(Array)
#4 /home/payon/public_html/wp-settings.php(486): do_action('plugins_loaded')
#5 /home/payon/public_html/wp-config.php(92): require_once('/home/payon/pub...')
#6 /home/payon/public_html/wp-load.php(50): require_once('/home/payon/pub...')
#7 /home/payon/public_html/wp-blog-header.php(13): require_once('/home/payon/pub...')
#8 /home/payon/public_html/index.php(17): require('/home/payon/pub...')
#9 {main}
  thrown in <b>/home/payon/public_html/wp-content/plugins/wp-rocket/inc/classes/class-plugin.php</b> on line <b>32</b><br />