The ornamental design for a steeringwheel for an automobile, as shown and described.
FIG. 1 is a front and right side perspective view of a steering wheel for an automobile showing my new design;
FIG. 2 is a rear and left side perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines shown in the drawings illustrate portions of the steering wheel for an automobile that are environmental structures and form no part of the claimed design.