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
 z z z z | z z z z | z z z z | z F E F ||{/F} B{/A} B !turn!G2- | G E2 F | E2 C2- | C2 C C || %8
{/C} B, C E F | G2 B2 | B/ c/ e/ d/ c/ B/ A/ G/ | F E2 E/ F/ || %12  