Imagine you're valuing a mature, stable, publicly traded consumer goods company with consistent cash flows. Walk me through how you would calculate Terminal Value within a DCF model for such a company. Furthermore, elaborate on the key considerations and specific methodologies you would use to determine the Cost of Equity and Cost of Debt when estimating the company's Weighted Average Cost of Capital (WACC).

假设你正在为一家业务成熟、现金流稳定的上市消费品公司进行估值。请你阐述在构建DCF模型时，如何处理终端价值（Terminal Value）的计算，并详细说明在估算该公司的加权平均资本成本（WACC）时，股权成本（Cost of Equity）和债务成本（Cost of Debt）的主要考量因素及具体计算方法。