We claim the ornamental design for a guiding tool for a sewing machine, as shown.
FIG. 1 is a perspective view of a guiding tool for a sewing machine according to our design;
FIG. 2 is a front view of the same;
FIG. 3 is a rear view of the same;
FIG. 4 is a top plan view of the same;
FIG. 5 is a bottom view of the same;
FIG. 6 is a left side view of the same;
FIG. 7 is a right side view of the same; and,
FIG. 8 is a sectional view taken along lines 8-8 in FIG. 4 for the purpose of showing how the inner bottom surface of the guiding tool partially inclines.