Add the flour to the oven bag. Close and shake the bag to distribute the flour. Place the bag in a 13 x 9 x 2-inch baking pan. Add the stock, sage, rosemary and thyme to the bag. Squeeze the bag to blend in the flour.Rinse the turkey with cold water and pat dry with a paper towel. Sprinkle the turkey evenly with the paprika, if desired. Add the turkey to the bag. Close the bag with the nylon tie. Cut 6 (1/2-inch) slits in the top of the bag. Insert a meat thermometer through a slit in the bag into the thickest part of the meat, making sure the thermometer is not touching the bone.Roast the turkey at 350°F. for 1 1/2 to 2 hours or until the thermometer reads 165°F.  Begin checking for doneness after 1 1/2 hours of roasting time. Let the turkey stand for 10 minutes before slicing.Remove the turkey from the bag. Pour the turkey liquid from the bag into a large cup. Skim off the fat.Heat the turkey liquid and gravy in a 2-quart saucepan over medium heat until it's hot. Serve with the turkey.