The ornamental design for a side body for an automobile, as shown and described.
FIG. 1 is a front perspective view of a side body for an automobile showing our new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a front view thereof; and,
FIG. 7 is a rear view thereof.
The claimed design is indicated by the relatively dark portions in the figures, while the relatively light portions are environmental and form no part of the claimed design. The relatively light portions include the door handles, side mirror, windows and interior.