src/Plum/Plum.php
public function getServer($server)
    {
        if (!isset($this->servers[$server])) {
            throw new \InvalidArgumentException(sprintf('The server "%s" is not registered.', $server));
        }

        return $this->servers[$server];
    }
public function getServer($server)
    {
        if (!isset($this->servers[$server])) {
            throw new \InvalidArgumentException(sprintf('The server "%s" is not registered.', $server));
        }

        return $this->servers[$server];
    }
Returns a server

@param type $server The server name

@return \Plum\Server\ServerInterface