src/AbstractHttpClient.php
public function getConfig($key)
    {
        if (!empty($this->config) && !empty($key)) {
            return $this->config->$key;
        }

        return $this->config;
    }
public function getConfig($key)
    {
        if (!empty($this->config) && !empty($key)) {
            return $this->config->$key;
        }

        return $this->config;
    }
@param $key

@return mixed