The ornamental design for a handbag, as shown and described.
FIG. 1 is a front perspective view of the handbag;
FIG. 2 is a left side view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a back view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The break lines indicate indeterminate length.
The broken lines showing the handles, portion of the straps, zippers, zipper pulls, metal clasp, hanging leather tabs and portions of the body of the bag are for the purposes of illustrating environment and forms no part of the claimed design.