The ornamental design for a handbag, as shown and described.
FIG. 1 is a front perspective view of an alternative embodiment of the handbag
FIG. 2 is a front view of the handbag;
FIG. 3 is a rear view of the handbag;
FIG. 4 is a left side view of the handbag;
FIG. 5 is a right side view of the handbag;
FIG. 6 is a top view of the handbag; and,
FIG. 7 is a bottom view of the handbag.
The broken line showing of the handle, portions of the hanging straps, buckle holes, rivets, metal closure flap, zipper, zipper pull, and portions of the body of the bag are included for the purpose of illustrating environmental structure and forms no part of the claimed design.