contentspec :: XParser ContentSpec
contentspec =
    oneOf' [ ("EMPTY",  peRef (word "EMPTY") >> return EMPTY)
           , ("ANY",    peRef (word "ANY") >> return ANY)
           , ("mixed",  peRef mixed >>= return . Mixed)
           , ("simple", peRef cp >>= return . ContentSpec)
           ]
contentspec :: XParser ContentSpec
contentspec =
    oneOf' [ ("EMPTY",  peRef (word "EMPTY") >> return EMPTY)
           , ("ANY",    peRef (word "ANY") >> return ANY)
           , ("mixed",  peRef mixed >>= return . Mixed)
           , ("simple", peRef cp >>= return . ContentSpec)
           ]
contentspec =
    oneOf' [ ("EMPTY",  peRef (word "EMPTY") >> return EMPTY)
           , ("ANY",    peRef (word "ANY") >> return ANY)
           , ("mixed",  peRef mixed >>= return . Mixed)
           , ("simple", peRef cp >>= return . ContentSpec)
           ]