The ornamental design for a sling, as shown and described.
FIG. 1 is a top-front-left side perspective view of a sling;
FIG. 2 is a top view of a portion of the sling represented by area 2 of FIG. 1;
FIG. 3 is a bottom view of a portion of the sling represented by area 2 of FIG. 1;
FIG. 4 is a left side view of a portion of the sling represented by area 2 of FIG. 1, a right side view being identical; and,
FIG. 5 is an enlarged cross-sectional view of the sling taken along line 5-5 of FIG. 1.
The broken line which extends along the center of the sling in FIGS. 1 and 2 is claimed stitching. The remainder of the broken lines in the drawings depict environmental matter that forms no part of the claimed design.
The sling is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.