I claim the ornamental design for a handbag, as shown and described.
1. Handbag
Figure 1.1 is a perspective view of a handbag, showing my new design;
Figure 1.2 is a front view thereof;
Figure 1.3 is a rear view thereof;
Figure 1.4 is a left view thereof;
Figure 1.5 is a right view thereof;
Figure 1.6 is a top view thereof; and,
Figure 1.7 is a bottom view thereof.
The short dashed lines shown in the drawings represent stitching and form part of the claimed design. The long dashed broken lines shown in the drawings depict portions of the handbag that form no part of the claimed design.