The ornamental design for handbag, as shown and described.
FIG. 1 is a front perspective view of a handbag showing my new design;
FIG. 2 is a front view of the handbag shown in FIG. 1;
FIG. 3 is a rear view of the handbag shown in FIG. 1;
FIG. 4 is a right side of the handbag shown in FIG. 1;
FIG. 5 is a left side view of the handbag shown in FIG. 1;
FIG. 6 is a top view of the handbag shown in FIG. 1; and,
FIG. 7 is a bottom view of the handbag shown in FIG. 1.
The broken line showing of the grommet, zipper pull, zipper track, zipper, rivets, and clasp is for illustrative purposes only and forms no part of the claimed design.