The ornamental design for a lock for a handbag, as shown and described.
FIG. 1 is a front perspective view of a lock for a handbag showing my new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a side view thereof;
FIG. 8 is a perspective view in open position thereof; and,
FIG. 9 is a perspective view in closed position thereof attached to an unclaimed handbag.
The portions of the lock for a handbag shown in broken lines are included for the purpose of showing unclaimed environmental structure only and form no part of the claimed design.