The ornamental design for a 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 thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a front perspective view of the handbag shown in FIG. 1 in an open position.
The evenly dashed broken lines depict portions of a handbag and form no part of the claim. The handle is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claim.