def T_stock(self, V_stock):
        """Return the amount of time at which the stock of materal will be
        depleted.

        :param V_stock: Volume of the stock of material
        :type V_stock: float

        :return: Time at which the stock will be depleted
        :rtype: float
        """
        return Stock.T_stock(self, V_stock, self.Q_stock()).to(u.hr)
Return the amount of time at which the stock of materal will be
        depleted.

        :param V_stock: Volume of the stock of material
        :type V_stock: float

        :return: Time at which the stock will be depleted
        :rtype: float