The ornamental design for a sewingmachine, as shown and described.
FIG. 1 is a front elevational view of a sewing machine;
FIG. 2 is a right side elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a top perspective view thereof; and,
FIG. 8 is a bottom perspective view thereof.
The broken line showing fasteners, flywheel, and additional parts is included for the purpose of illustrating environmental structure and forms no part of the claimed design.