'Constructor.
A Cursor constructed with no arguments points the first result of any
query. If such a Cursor is used as an end_cursor no results will ever be
returned.'

@datastore_rpc._positional(1)
def __init__(self, urlsafe=None, _cursor_bytes=None):

    super(Cursor, self).__init__()
    if (urlsafe is not None):
        if (_cursor_bytes is not None):
            raise datastore_errors.BadArgumentError('Can    only    specify    one    of    urlsafe    and    _cursor_bytes')
        _cursor_bytes = self._urlsafe_to_bytes(urlsafe)
    if (_cursor_bytes is not None):
        self.__cursor_bytes = _cursor_bytes
    else:
        self.__cursor_bytes = ''
