Ppr009.hs:5:15: error: Not in scope: data constructor ‘Bitstream’

Ppr009.hs:7:7: error:
    Not in scope: ‘S.concatMap’
    No module named ‘S’ is imported.

Ppr009.hs:7:27: error:
    Not in scope: ‘GV.stream’
    No module named ‘GV’ is imported.

Ppr009.hs:8:7: error:
    Not in scope: ‘S.sized’
    No module named ‘S’ is imported.

Ppr009.ppr.hs:4:15: error:
    Not in scope: data constructor ‘Bitstream’

Ppr009.ppr.hs:6:5: error:
    Not in scope: ‘S.concatMap’
    No module named ‘S’ is imported.

Ppr009.ppr.hs:6:25: error:
    Not in scope: ‘GV.stream’
    No module named ‘GV’ is imported.

Ppr009.ppr.hs:6:38: error:
    Not in scope: ‘S.sized’
    No module named ‘S’ is imported.