The ornamental design for a tote bag, as shown and described.
FIG. 1 is a front perspective view of an ornamental design for a tote bag according to the present invention;
FIG. 2 is a first side view thereof;
FIG. 3 is a second side view thereof;
FIG. 4 is a top view thereof; and,
FIG. 5 is a bottom view thereof.
The broken lines showing stitching, shoes and interior side pouch are for the purposes of illustrating environment and form no part of the claimed design.