0 400   0   # Simple raw string
 0 400   0   r''
 1 400   0   
 0 400   0   # Raw f-string
 0 400   0   rf''
 0 400   0   fr''
 1 400   0   
 0 400   0   # Raw byte string
 0 400   0   rb''
 0 400   0   br''
 1 400   0   
 0 400   0   # Raw unicode strings: ur'' is valid in 2.7 (but not in 3) -- always lexed as
 0 400   0   # valid; ru'' is never valid
 0 400   0   ru''
 0 400   0   ur''
 1 400   0   
 1 400   0