src/Payum/Core/PayumBuilder.php
public function addGatewayFactoryConfig($name, array $config)
    {
        $currentConfig = isset($this->gatewayFactoryConfigs[$name]) ? $this->gatewayFactoryConfigs[$name] : [];
        $this->gatewayFactoryConfigs[$name] = array_replace_recursive($currentConfig, $config);

        return $this;
    }
public function addGatewayFactoryConfig($name, array $config)
    {
        $currentConfig = isset($this->gatewayFactoryConfigs[$name]) ? $this->gatewayFactoryConfigs[$name] : [];
        $this->gatewayFactoryConfigs[$name] = array_replace_recursive($currentConfig, $config);

        return $this;
    }
@param string $name
@param array  $config

@return static