The ornamental design for a bag, as shown and described.
FIG. 1 is a front perspective view of a bag showing my new design;
FIG. 2 is a rear perspective view of the bag;
FIG. 3 is a front view of the bag;
FIG. 4 is a rear view of the bag;
FIG. 5 is a left side view of the bag;
FIG. 6 is a top view of the bag;
FIG. 7 is a bottom view of the bag; and,
FIG. 8 is a cross-sectional view of the bag along the line 8-8 of FIG. 6.
The evenly spaced broken lines showing the container are for the purposes of illustrating environment. The dot-dashed lines illustrate the boundaries of the claim. Neither of the broken lines are part of the claimed design.