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 view 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 show in FIG. 1.
The broken line showing of the zippers, front label piece, carabiner (non-locking), grommets, strap is for illustrative purposes only and forms no part of the claimed design.