flac: Add example for adding a cue sheet block

[lazka]

Originally reported by: Gates Wong (Bitbucket: gatesice, GitHub: Unknown)

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from mutagen import flac

cue_file_utf8 = "手嶌葵 - 春の歌集.utf8.cue"

with open(cue_file_utf8) as fp:
    cue_obj = flac.CueSheet(fp)

It raises the error:

/Library/Python/2.7/site-packages/mutagen/flac.pyc in read(self, size)
     65         if size >= 0 and len(data) != size:
     66             raise error("file said %d bytes, read %d bytes" % (
---> 67                         size, len(data)))
     68         return data
     69 

error: file said 396 bytes, read 0 bytes

If I use:

with open(cue_file_utf8) as fp:
    cue_obj = flac.CueSheet(fp.read())

I got:

/Library/Python/2.7/site-packages/mutagen/flac.pyc in read(self, size)
     65         if size >= 0 and len(data) != size:
     66             raise error("file said %d bytes, read %d bytes" % (
---> 67                         size, len(data)))
     68         return data
     69 

error: file said 36 bytes, read 33 bytes

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• Bitbucket: https://bitbucket.org/lazka/mutagen/issue/224

[lazka]

Original comment by Christoph Reiter (Bitbucket: lazka, GitHub: lazka):

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mutagen can't read cue sheet files. It can only read/write flac cue sheet block [0]

[0] https://xiph.org/flac/format.html#metadata_block_cuesheet