FIG. 1 is an isometric view of a cart; FIG. 2 is a right side view of the cart; FIG. 3 is a left side view of the cart; FIG. 4 is a top view of the cart; FIG. 5 is a bottom view of the cart; FIG. 6 is a back view of the cart; and, FIG. 7 is a front view of the cart. The broken lines in the drawings are to show portions of the cart that form no part of the claimed design.