def _tf_vpc_config(lambda_config):
    """Compute VPC configuration from the Lambda config."""
    result = {}
    vpc_config = lambda_config.get('vpc_config', {})
    if not vpc_config:
        return result

    if 'security_group_ids' in vpc_config:
        result['vpc_security_group_ids'] = vpc_config['security_group_ids']
    if 'subnet_ids' in vpc_config:
        result['vpc_subnet_ids'] = vpc_config['subnet_ids']

    return result