The ornamental design for a sewingmachine, as shown and described.
FIG. 1 is a front view of a sewing machine, showing our new design;
FIG. 2 is a rear view thereof wherein the broken lines are included to show unclaimed environment only and form no part of the claimed design;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a lateral view (right side) thereof;
FIG. 6 is a lateral view (left side) thereof; and,
FIG. 7 is a perspective view thereof wherein the portions of the article shown broken away with solid, curvy, cut-off lines in FIGS. 3 through 7 indicate that any portion of the article beyond what is shown forms no part of the claimed design.