The ornamental design for a portion of a handbag, as shown and described.
FIG. 1 is a perspective view of a portion of a handbag showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The lighter weight dash-dot broken lines showing portions of the handbag for the purposes of illustrating environment. The bold dot-dash lines represent the metes and bounds of the claim. Both types of lines form no part of the claimed design.