I claim the ornamental design for a handle for suitcase, as shown and described.
FIG. 1 is a perspective view of a handle for suitcase showing the 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 view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line showing of the handle for suitcase is included for the purpose of illustrating portions of the article and forms no part of the claimed design.