Changing lyrics' font

[Oscar A. Valdez]

I would like to be able to "override" and "revert" the lyrics' font from bold
back to normal. In this example, I'm trying to do it for the syllable "Di-", but
all I get is a parse error. Can someone point out how to do it?

\score {
  \addlyrics
    \context Staff = Antifona {
       ...              
       ...
    }
  \context Lyrics
    \lyrics {
      To- da la tie- rra te a- do- ra,
      \property Lyrics.LyricText \override #'font-series = #'bold
      Di-
      \property Lyrics.LyricText \revert #'font-series
      os, y sal- mo- dia pa- ra ti,
      can- ta sal- mos a tu nom- bre, Se- nor.
    }
}


-- 
Oscar A. Valdez

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