cannot decode "é"

[mkouhei]

Traceback (most recent call last):
  File "./debbuild.py", line 429, in <module>
    main()
  File "./debbuild.py", line 408, in main
    passphrase=args.passphrase) is False:
  File "/usr/lib/python2.7/dist-packages/pydebsign/debsign.py", line 286, in debsign_process
    if dbsg.signing_dsc() is False:
  File "/usr/lib/python2.7/dist-packages/pydebsign/debsign.py", line 139, in signing_dsc
    fileobj.write(signed_data.data.decode('utf-8'))
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in position 239: ordinal not in range(128)