The ornamental design for a pump, as shown and described.
FIG. 1 is a top, front and left side perspective view of a pump, showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is an enlarged view of the features visible in the area noted by circle 3 on FIG. 2, shown from a bottom, front and left perspective view;
FIG. 4 is a left side view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is an enlarged view of the features visible in the area noted by circle 7 on FIG. 6, shown from a top, rear and left perspective view;
FIG. 8 is a top view thereof; and,
FIG. 9 is a bottom view thereof.
The long dash, short dash lines in the drawings define the bounds of the claimed design and form no part thereof. The dash-dash broken lines in the drawings depict portions of the pump that form no part of the claimed design.