The ornamental design for a sleepmanagementdevice, as shown and described.
FIG. 1 is a front perspective view of a sleep management device showing our new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The claimed design is indicated by the relatively dark portions in the figures. The relatively light portions, specifically the rear hook portion and the left side button portion form no part of the claimed design.
The drawings include grayscale surface shading which illustrates contour, not any particular color. The drawings include shadows and reflections which indicate contour, not surface ornamentation.