// Copy paste :(
        // Should have look like this
        // Brew(ref FillableContainer) { code... }
        // Brew(ref Can can) => Brew(can);
        // Brew(ref Cup cup) => Brew(cup);

        public string Brew(ref Cup cup)
        {
            if ((!FilterHolder.HasCleanFilterWithIngredient()) || (WaterMlAmount <= 0))
            {
                return("Couldn't brew!");
            }
            else
            {
                Brewage brewage = FilterHolder.Filter.PourWater(WaterMlAmount);
                cup.FillWithBrewage(brewage);

                WaterMlAmount = 0;

                return($"{FilterHolder.Filter.IngredentName} was brewed in cup.");
            }
        }