def set_open_sheet(self, sheet: Union[str, odf.table.Table, None]=None) -> None:

        """Set which sheet is open in the document

        When the user first opens the spreadsheet, their view will be on this

        sheet. You can provide a sheet name string or sheet object. With no

        argument, defaults to ``self.sheet``.

        """

        if sheet is None:

            sheet = self.sheet

        if not isinstance(sheet, str):

            sheet = sheet.getAttribute('name')

            if not isinstance(sheet, str):

                raise ValueError("sheet argument has no name for setting")

        self.set_config(self.view, 'ActiveTable', sheet, 'string')

    def use_sheet(self, name: str) -> odf.table.Table:

        """Switch the active sheet ``self.sheet`` to the one with the given name

        If there is no sheet with the given name, create it and append it to

        the spreadsheet first.

        If the current active sheet is empty when this method is called, it

        will be removed from the spreadsheet.

        """

        try:

            empty_sheet = not self.sheet.hasChildNodes()

        except AttributeError:

            empty_sheet = False

        if empty_sheet:

            self.document.spreadsheet.removeChild(self.sheet)

        self.sheet = self.ensure_child(

            self.document.spreadsheet, odf.table.Table, name=name,

        )

        return self.sheet

    ### Initialization hooks

    def init_settings(self) -> None:

        """Hook called to initialize settings

        This method is called by __init__ to populate

        ``self.document.settings``. This implementation creates the barest

        skeleton structure necessary to support other methods, in particular

        ``lock_first_row``.

        """

        view_settings = self.ensure_child(

            self.document.settings, odf.config.ConfigItemSet, name='ooo:view-settings',

        )

        views = self.ensure_child(

            view_settings, odf.config.ConfigItemMapIndexed, name='Views',

        )

        self.view = self.ensure_child(views, odf.config.ConfigItemMapEntry)

        self.set_config(self.view, 'ViewId', 'view1')

    def init_styles(self) -> None:

        """Hook called to initialize settings

        This method is called by __init__ to populate

        ``self.document.styles``. This implementation creates basic building

        block cell styles often used in financial reports.

        """

        styles = self.document.styles

        self.style_bold = self.ensure_child(

            styles, odf.style.Style, name='Bold', family='table-cell',

        )

        self.ensure_child(

            self.style_bold, odf.style.TextProperties, fontweight='bold',

        )

        date_style = self.replace_child(styles, odf.number.DateStyle, name='ISODate')

        date_style.addElement(odf.number.Year(style='long'))

        date_style.addElement(odf.number.Text(text='-'))

        date_style.addElement(odf.number.Month(style='long'))

        date_style.addElement(odf.number.Text(text='-'))

        date_style.addElement(odf.number.Day(style='long'))

        self.style_date = self.ensure_child(

            styles,

            odf.style.Style,

            name=f'{date_style.getAttribute("name")}Cell',

            family='table-cell',

            datastylename=date_style,

        )

        self.style_starttext: odf.style.Style

        self.style_centertext: odf.style.Style

        self.style_endtext: odf.style.Style

        for textalign in ['start', 'center', 'end']:

            aligned_style = self.replace_child(

                styles, odf.style.Style, name=f'{textalign.title()}Text',

            )

            aligned_style.setAttribute('family', 'table-cell')

            aligned_style.addElement(odf.style.ParagraphProperties(textalign=textalign))

            setattr(self, f'style_{textalign}text', aligned_style)

    ### Properties

    def set_properties(self, *,

                       created: Optional[datetime.datetime]=None,

                       generator: str='conservancy_beancount',

    ) -> None:

        if created is None:

            created = datetime.datetime.now()

        created_elem = self.ensure_child(self.document.meta, odf.meta.CreationDate)

        created_elem.childNodes.clear()

        created_elem.addText(created.isoformat())

        generator_elem = self.ensure_child(self.document.meta, odf.meta.Generator)

        generator_elem.childNodes.clear()

        generator_elem.addText(f'{generator}/{VERSION} {TOOLSVERSION}')

    ### Rows and cells

    def add_row(self, *cells: odf.table.TableCell, **attrs: Any) -> odf.table.TableRow:

        row = odf.table.TableRow(**attrs)

        for cell in cells:

            row.addElement(cell)

        self.sheet.addElement(row)

        return row

    def balance_cell(self, balance: Balance, **attrs: Any) -> odf.table.TableCell:

        balance = balance.clean_copy() or balance

        balance_currency_count = len(balance)

        if balance_currency_count == 0:

            return self.float_cell(0, **attrs)

        elif balance_currency_count == 1:

            amount = next(iter(balance.values()))

            attrs['stylename'] = self.merge_styles(

                attrs.get('stylename'), self.currency_style(amount.currency),

            )

            return self.currency_cell(amount, **attrs)

        else:

            lines = [babel.numbers.format_currency(

                number, currency, locale=self.locale, format_type=self.currency_fmt_key,

            ) for number, currency in balance.values()]

            attrs['stylename'] = self.merge_styles(

                attrs.get('stylename'), self.style_endtext,

            )

            return self.multiline_cell(lines, **attrs)

    def currency_cell(self, amount: data.Amount, **attrs: Any) -> odf.table.TableCell:

        if 'stylename' not in attrs:

            attrs['stylename'] = self.currency_style(amount.currency)

        number, currency = amount

        cell = odf.table.TableCell(valuetype='currency', value=number, **attrs)

        cell.addElement(odf.text.P(text=babel.numbers.format_currency(

            number, currency, locale=self.locale, format_type=self.currency_fmt_key,

        )))

        return cell

    def date_cell(self, date: datetime.date, **attrs: Any) -> odf.table.TableCell:

        attrs.setdefault('stylename', self.style_date)

        cell = odf.table.TableCell(valuetype='date', datevalue=date, **attrs)

        cell.addElement(odf.text.P(text=date.isoformat()))

        return cell

    def float_cell(self, value: Union[int, float, Decimal], **attrs: Any) -> odf.table.TableCell:

        cell = odf.table.TableCell(valuetype='float', value=value, **attrs)

        cell.addElement(odf.text.P(text=str(value)))

        return cell

    def _meta_link_pairs(self, links: Iterable[Optional[str]]) -> Iterator[Tuple[str, str]]:

        for href in links:

            if href is None:

                continue

            elif self.rt_wrapper is not None:

                rt_ids = self.rt_wrapper.parse(href)

                rt_href = rt_ids and self.rt_wrapper.url(*rt_ids)

            else:

                rt_ids = None

                rt_href = None

            if rt_ids is None or rt_href is None:

                # '..' pops the ODS filename off the link path. In other words,

                # make the link relative to the directory the ODS is in.

                href_path = Path('..', href)

                href = str(href_path)

                text = href_path.name

            else:

                rt_path = urlparse.urlparse(rt_href).path

                if rt_path.endswith('/Ticket/Display.html'):

                    text = rtutil.RT.unparse(*rt_ids)

                else:

                    text = urlparse.unquote(Path(rt_path).name)

                href = rt_href

            yield (href, text)

    def meta_links_cell(self, links: Iterable[Optional[str]], **attrs: Any) -> odf.table.TableCell:

        return self.multilink_cell(self._meta_link_pairs(links), **attrs)

    def multiline_cell(self, lines: Iterable[Any], **attrs: Any) -> odf.table.TableCell:

        cell = odf.table.TableCell(valuetype='string', **attrs)

        for line in lines:

            cell.addElement(odf.text.P(text=str(line)))

        return cell