The ornamental design for a practiceattachment for a golf putter, as shown and described.
FIG. 1 is a perspective view of a practice attachment for a golf putter according to my new design;
FIG. 2 is a side elevational view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a front elevational view thereof; and
FIG. 6 is a rear elevational view thereof.
FIG. 7 is a perspective view of an alternative embodiment of a practice attachment for a golf putter according to my new design;
FIG. 8 is a top plan view thereof; and,
FIG. 9 is a bottom plan view thereof.
The broken lines showing a) the wing of a thumbscrew and b) the head of a button-head cap screw, are for illustrative purposes only and form no part of the claimed design.