override StaffSymbol.line-count

[Bernard]

Hi,

I am new to Lilypond.

I would like to use a 2 line staff with the code :

-----------------------------------------

\version "2.16.2"

timb = \drummode {
         timh4 ssh
       }

  <<
    \new DrumStaff \with {
      drumStyleTable = #timbales-style
      \override StaffSymbol.line-count = #2  # generate syntax error
    } <<
      \set Staff.instrumentName = #"timbales"
      \timb
    >>


----------------------------------------

Which result in errorlog in Frescobaldi :

Starting lilypond 2.16.2 [test3.ly]...
Processing `/tmp/frescobaldi-Gxm9Z9/tmpdW9FQu/test3.ly'
Parsing...
/tmp/frescobaldi-Gxm9Z9/tmpdW9FQu/test3.ly:10:27: error: syntax error, 
unexpected '.', expecting SCM_FUNCTION or SCM_IDENTIFIER or SCM_TOKEN
      \override StaffSymbol
                           .line-count = #2
/tmp/frescobaldi-Gxm9Z9/tmpdW9FQu/test3.ly:10:41: warning: Ignoring 
non-music expression
      \override StaffSymbol.line-count =
                                         #2
/tmp/frescobaldi-Gxm9Z9/tmpdW9FQu/test3.ly:17:0: error: syntax error, 
unexpected '}'

}
fatal error: failed files: "/tmp/frescobaldi-Gxm9Z9/tmpdW9FQu/test3.ly"
Exited with return code 1.

--------------------

This code was a snippet from :
http://lsr.di.unimi.it/LSR/Search?q=percussion  Section adding drum parts

and 
http://www.lilypond.org/doc/v2.19/Documentation/source/Documentation/snippets/percussion

which causes in the full version the same error.

How can I solve this?  Thanks.

Bernard