The ornamental design for a frame, substantially as shown and described.
FIG. 1 is a front perspective view of a version of the frame showing the new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a right side elevation view thereof; and,
FIG. 7 is a left side elevation view thereof.
The broken lines in the drawings are for purposes of illustrating environmental subject matter that forms no part of the claimed design. The unshown bottom plan view is the mirror image of FIG. 5.