Generate a piece of music.  
X:1
T:Music21 Fragment
C:Music21
L:1/4
M:none
I:linebreak $
K:none
V:1 treble 
V:1
{/C} B, C{/F} E F | G G B2 | c2 c2- | c B G2 ||{/G} E F E E | E F !turn!G2 | F E F E/ D/ | %7
 C D C2 || %8  