override Stem beamed-lengths

[cl]

I'm new here and new to lilypond, but I read the posts from a few years

ago about tweaking the stem lengths of beamed notes.  The posts deal

with earlier versions.

 

This code

 

\version "2.10.33"

\relative c' {

a8[ g]

\override Stem #'beamed-lengths = #'(20) a8[ g]

\revert Stem #'beamed-lengths

a8[ g]

}

 

gives me this warning

warning: can't find property type-check for `beamed-lengths' (backend-type?).  perhaps a typing error?

 

I believe I copied the override code correctly from the lilypond-user archive. 

The beamed-lengths property is in the stem-interface, but not in Stem according to the documentation.

Help?

Eric