Accidentals with 'modern' option doesn't work

[Anna Choma]

Hi,

I need to use modern style in the accidentals. But it doesn't work. 
What am I doing wrong? There is no difference to 'default' option. My 
version is 2.2.6

#(set-global-staff-size 16)
\header { tagline = "" }
Nuty = \notes  {
       \time 4/4
       #(set-accidental-style 'modern)
       d'8\startGroup dis''' gis' cis'''
       \stemDown g'\stopGroup c'''' r4
       d'8 dis''' gis' cis'''
       r g' c'''' r
       d'[\startGroup r dis' \[gis''']
       cis' g'''\] c'\stopGroup r}

\score { \Nuty
         \paper { paperheight = 21.0 \cm
                  linewidth = 134\mm
                  pagenumber = no
                  noindent = 0\mm
                  \context {
                        \StaffContext \consists 
"Horizontal_bracket_engraver"}
                  }
                }

Best regards,

Anna Choma