Changing basic distance between stanzas

[Joshua Nichols]

I am looking for a tweak to decrease or increase the vertical distance between multiple stanzas.

I found this online (not in the manual):

\context {
    \Lyrics
    minimumVerticalExtent = #'(0 . 0)
  }

​But, when I compile (with any number in the variable) I get this message:

warning: cannot find property type-check for `minimumVerticalExtent' (translation-type?). perhaps a typing error?

warning: skipping assignment

Here is an example:

\version "2.18.2"

notesA = {
  c'
}

vOne = \lyricmode {
  a
}

vTwo = \lyricmode {
  b
}

\score {
  <<
    \new Voice = "mel" { \notesA }
    \new Lyrics \lyricsto "mel" { \vOne }
    \new Lyrics \lyricsto "mel" { \vTwo }
 
   
  >>
  \layout {
      \context {
      \Lyrics
      minimumVerticalExtent = #'(0 . 0)
      }
    }
}

Help?

​Sincerely,

Josh