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

        return $this;
    }
public function addCoreGatewayFactoryConfig(array $config)
    {
        $currentConfig = $this->coreGatewayFactoryConfig ?: [];
        $this->coreGatewayFactoryConfig = array_replace_recursive($currentConfig, $config);

        return $this;
    }
@param array $config

@return static