src/Config.php
public function get($name)
    {
        $value = null;

        // get value
        if (false === strpos($name, '.')) {
            $value = isset($this->config[$name]) ? $this->config[$name] : null;
        } else {
            $value = $this->config;
            foreach (explode('.', $name) as $field) {
                if (!isset($value[$field])) {
                    return null;
                }

                $value = $value[$field];
            }
        }

        // replace value with env variable
        $value = $this->replaceConfigValuePlaceholders($value);

        return $value;
    }
public function get($name)
    {
        $value = null;

        // get value
        if (false === strpos($name, '.')) {
            $value = isset($this->config[$name]) ? $this->config[$name] : null;
        } else {
            $value = $this->config;
            foreach (explode('.', $name) as $field) {
                if (!isset($value[$field])) {
                    return null;
                }

                $value = $value[$field];
            }
        }

        // replace value with env variable
        $value = $this->replaceConfigValuePlaceholders($value);

        return $value;
    }
@param string $name

@return array|string|int|null

@throws \RuntimeException when param defined as env variable but env variable not defined