File "c:\python27\Lib\json\__init__.py", line 189, in dump

    for chunk in iterable:

  File "c:\python27\Lib\json\encoder.py", line 431, in _iterencode

    for chunk in _iterencode_list(o, _current_indent_level):

  File "c:\python27\Lib\json\encoder.py", line 313, in _iterencode_list

    yield buf + _encoder(value)

UnicodeDecodeError: 'utf8' codec can't decode byte 0xb7 in position 2: invalid start byte