How to use the openpyxl.cell.coordinate_from_string function in openpyxl

if not range_string:
            if  start_row is None or start_column is None or end_row is None or end_column is None:
                msg = "You have to provide a value either for "\
                      "'coordinate' or for 'start_row', 'start_column', 'end_row' *and* 'end_column'"
                raise InsufficientCoordinatesException(msg)
            else:
                range_string = '%s%s:%s%s' % (get_column_letter(start_column + 1), start_row + 1, get_column_letter(end_column + 1), end_row + 1)
        elif len(range_string.split(':')) != 2:
                msg = "Range must be a cell range (e.g. A1:E1)"
                raise InsufficientCoordinatesException(msg)
        else:
            range_string = range_string.replace('$', '')

        # Make sure top_left cell exists - is this necessary?
        min_col, min_row = coordinate_from_string(range_string.split(':')[0])
        max_col, max_row = coordinate_from_string(range_string.split(':')[1])
        min_col = column_index_from_string(min_col)
        max_col = column_index_from_string(max_col)
        # Blank out the rest of the cells in the range
        for col in xrange(min_col, max_col + 1):
            for row in xrange(min_row, max_row + 1):
                if not (row == min_row and col == min_col):
                    # PHPExcel adds cell and specifically blanks it out if it doesn't exist
                    self._get_cell('%s%s' % (get_column_letter(col), row)).value = None
                    self._get_cell('%s%s' % (get_column_letter(col), row)).merged = True

        if range_string not in self._merged_cells:
            self._merged_cells.append(range_string)

def get_range_boundaries(range_string, row_offset=0, column_offset=1):

    if ':' in range_string:
        min_range, max_range = range_string.split(':')
        min_col, min_row = coordinate_from_string(min_range)
        max_col, max_row = coordinate_from_string(max_range)

        min_col = column_index_from_string(min_col)
        max_col = column_index_from_string(max_col) + 1

    else:
        min_col, min_row = coordinate_from_string(range_string)
        min_col = column_index_from_string(min_col)
        max_col = min_col + column_offset
        max_row = min_row + row_offset

    return (min_col, min_row, max_col, max_row)

:param row: number of rows to offset
        :type row: int

        :param column: number of columns to offset
        :type column: int

        :rtype: tuples of tuples of :class:`openpyxl.cell.Cell`

        """
        if ':' in range_string:
            # R1C1 range
            result = []
            min_range, max_range = range_string.split(':')
            min_col, min_row = coordinate_from_string(min_range)
            max_col, max_row = coordinate_from_string(max_range)
            if column:
                min_col = get_column_letter(
                        column_index_from_string(min_col) + column)
                max_col = get_column_letter(
                        column_index_from_string(max_col) + column)
            min_col = column_index_from_string(min_col)
            max_col = column_index_from_string(max_col)
            cache_cols = {}
            for col in xrange(min_col, max_col + 1):
                cache_cols[col] = get_column_letter(col)
            rows = xrange(min_row + row, max_row + row + 1)
            cols = xrange(min_col, max_col + 1)
            for row in rows:
                new_row = []
                for col in cols:
                    new_row.append(self.cell('%s%s' % (cache_cols[col], row)))

def get_range_boundaries(range_string, row_offset=0, column_offset=1):

    if ':' in range_string:
        min_range, max_range = range_string.split(':')
        min_col, min_row = coordinate_from_string(min_range)
        max_col, max_row = coordinate_from_string(max_range)

        min_col = column_index_from_string(min_col)
        max_col = column_index_from_string(max_col) + 1

    else:
        min_col, min_row = coordinate_from_string(range_string)
        min_col = column_index_from_string(min_col)
        max_col = min_col + column_offset
        max_row = min_row + row_offset

    return (min_col, min_row, max_col, max_row)

def read_dimension(source):
    min_row = min_col =  max_row = max_col = None
    DIMENSION_TAG = '{%s}dimension' % SHEET_MAIN_NS
    DATA_TAG = '{%s}sheetData' % SHEET_MAIN_NS
    it = iterparse(source, tag=[DIMENSION_TAG, DATA_TAG])
    for _event, element in it:
        if element.tag == DIMENSION_TAG:
            dim = element.get("ref")
            if ':' in dim:
                start, stop = dim.split(':')
            else:
                start = stop = dim
            min_col, min_row = coordinate_from_string(start)
            max_col, max_row = coordinate_from_string(stop)
            return min_col, min_row, max_col, max_row
        elif element.tag == DATA_TAG:
            # Dimensions missing
            break
        element.clear()

:type range_string: string

        :param row: number of rows to offset
        :type row: int

        :param column: number of columns to offset
        :type column: int

        :rtype: tuples of tuples of :class:`openpyxl.cell.Cell`

        """
        if ':' in range_string:
            # R1C1 range
            result = []
            min_range, max_range = range_string.split(':')
            min_col, min_row = coordinate_from_string(min_range)
            max_col, max_row = coordinate_from_string(max_range)
            if column:
                min_col = get_column_letter(
                        column_index_from_string(min_col) + column)
                max_col = get_column_letter(
                        column_index_from_string(max_col) + column)
            min_col = column_index_from_string(min_col)
            max_col = column_index_from_string(max_col)
            cache_cols = {}
            for col in xrange(min_col, max_col + 1):
                cache_cols[col] = get_column_letter(col)
            rows = xrange(min_row + row, max_row + row + 1)
            cols = xrange(min_col, max_col + 1)
            for row in rows:
                new_row = []
                for col in cols:

def get_range_boundaries(range_string, row_offset=0, column_offset=1):

    if ':' in range_string:
        min_range, max_range = range_string.split(':')
        min_col, min_row = coordinate_from_string(min_range)
        max_col, max_row = coordinate_from_string(max_range)

        min_col = column_index_from_string(min_col)
        max_col = column_index_from_string(max_col) + 1

    else:
        min_col, min_row = coordinate_from_string(range_string)
        min_col = column_index_from_string(min_col)
        max_col = min_col + column_offset
        max_row = min_row + row_offset

    return (min_col, min_row, max_col, max_row)

def write_worksheet_sheetviews(doc, worksheet):
    start_tag(doc, 'sheetViews')
    start_tag(doc, 'sheetView', {'workbookViewId': '0'})
    selectionAttrs = {}
    topLeftCell = worksheet.freeze_panes
    if topLeftCell:
        colName, row = coordinate_from_string(topLeftCell)
        column = column_index_from_string(colName)
        pane = 'topRight'
        paneAttrs = {}
        if column > 1:
            paneAttrs['xSplit'] = str(column - 1)
        if row > 1:
            paneAttrs['ySplit'] = str(row - 1)
            pane = 'bottomLeft'
            if column > 1:
                pane = 'bottomRight'
        paneAttrs.update(dict(topLeftCell=topLeftCell,
                              activePane=pane,
                              state='frozen'))
        tag(doc, 'pane', paneAttrs)
        selectionAttrs['pane'] = pane
        if row > 1 and column > 1: