How to use the pyexcelerate.Range.Range.coordinate_to_string function in PyExcelerate

z = '">%.15g' % (cell)
        elif type == DataTypes.INLINE_STRING:
            z = '" t="inlineStr">%s' % escape(
                to_unicode(cell))
        elif type == DataTypes.DATE:
            z = '">%s' % (DataTypes.to_excel_date(cell))
        elif type == DataTypes.FORMULA:
            z = '">%s' % (cell[1:]) # Remove equals sign.
        elif type == DataTypes.BOOLEAN:
            z = '" t="b">%d' % (cell)

        if style:
            return "

def __str__(self):
        return Range.coordinate_to_string(
            self._start) + ":" + Range.coordinate_to_string(self._end)

def __str__(self):
        return Range.coordinate_to_string(
            self._start) + ":" + Range.coordinate_to_string(self._end)

def get_xml(self):
        attrs = {
            'topLeftCell':
            Range.Range.coordinate_to_string((self.y + 1, self.x + 1))
        }
        if self.freeze:
            attrs['state'] = 'frozen'
        if self.x:
            attrs['xSplit'] = self.x
        if self.y:
            attrs['ySplit'] = self.y
        attr_str = " ".join('%s="%s"' % item for item in sorted(attrs.items()))
        return to_unicode("" % attr_str)