'Convert bytestring columns (dtype.kind=\'S\') to unicode (dtype.kind=\'U\') assuming
ASCII encoding.
Internally this changes string columns to represent each character in the string
with a 4-byte UCS-4 equivalent, so it is inefficient for memory but allows Python
3 scripts to manipulate string arrays with natural syntax.
The ``python3_only`` parameter is provided as a convenience so that code can
be written in a Python 2 / 3 compatible way::
>>> t = Table.read(\'my_data.fits\')
>>> t.convert_bytestring_to_unicode(python3_only=True)
Parameters
python3_only : bool
Only do this operation for Python 3'

def convert_bytestring_to_unicode(self, python3_only=False):

    self._convert_string_dtype(u'S', u'U', python3_only)
