* Any user action (a keypress or mouse click) eventually funnels down to * this method which ensures that only the passed in element is checked.

* `_allTabs()` returns all the tabs in the tab panel.

* `_allHeadings` returns all the headings in the accordion.

* `_selectTab()` marks the given tab as selected. * Additionally, it unhides the panel corresponding to the given tab.

* `_panelForHeading` returns the panel that the given heading controls.

* `_toggleChecked()` calls the `checked` setter and flips its state. * Because `_toggleChecked()` is only caused by a user action, it will *

* `_togglePressed()` calls the `pressed` setter and flips its state. * Because `_togglePressed()` is only caused by a user action, it will *

* Remove any previous labels. * Find the new element to label. * Label it.

* `_allPanels()` returns all the panels in the tab panel. This function * could memoize the result if the DOM queries ever become a performance

* `_animate` animates a translation on the Y axis from one offset to * another. It takes care of promoting all the elements, making sure they

* Mark the passed in node as being checked by setting `aria-checked=true`, * and make it focusable by setting `tabindex=0`.

* `_collapsePanel` puts the given panel in the collapsed state.

* `_expandPanel` puts the given panel in the expanded state.

* `_linkPanels()` links up tabs with their adjacent panels using * `aria-controls` and `aria-labelledby`. Additionally, the method makes * s

* Only one `HowtoRadioButton` should be checked at any time. To ensure * this, loop through all `HowtoRadioButton` children and set them to

* `_allPanels` returns all the panels in the accordion. This function could * memoize the result if the DOM queries ever become a performance iss

* `_animateIn` determines the height of the panel and uses that value for * an expanding animation.

* Same as `_animateIn` but in the other direction.

* `_animatePanelForHeading` animates the expansion of a panel, provided * there is no other animation running.

* `_collapseHeading` puts the given heading in the collapsed state.

* `_expandHeading` puts the given heading in the expanded state.

* If there is a for property, return the element with that id. * Else, return the explicitly labeled child. * Else, return the first element

* `_firstHeading` returns the first heading.

* `_firstTab()` returns the first tab.

* Call `focus()` on the passed in node to direct keyboard focus to it.

* `_isHeading` returns true if the given element * is a `<howto-accordion-heading>`.

* `_lastHeading` returns the last heading.

* `_lastTab()` returns the last tab.

* `_nextHeading` gets the heading that comes after the currently selected * one, wrapping around when reaching the last heading.

* A helper for when the user tries to moves forwards through the * `HowtoRadioGroup` using their keyboard. Return the `HowtoRadioButton` * c

* `_nextTab()` gets the tab that comes after the currently selected one, * wrapping around when reaching the last tab.

* `_panelForTab()` returns the panel that the given tab controls.

* `_prevHeading` returns the heading that comes before the currently * selected one, wrapping around when reaching the first one.

* A helper for when the user tries to moves backwards through the * `HowtoRadioGroup` using their keyboard. Return the `HowtoRadioButton` *

* `_prevTab()` returns the tab that comes before the currently selected * one, wrapping around when reaching the first one.

* This method is called in response to a user pressing a key to move * forwards through the `HowtoRadioGroup`. Check to see if the currently

* This method is called in response to a user pressing a key to move * backwards through the `HowtoRadioGroup`. Check to see if the currently

* Check if a property has an instance value. If so, copy the value, and * delete the instance property so it doesn't shadow the class property

* `buildMocha` builds a new instance of the Mocha test runner that has sourced * all the e2e test files. * @returns A promise that resolves when Moc

* `reset()` marks all tabs as deselected and hides all the panels.

* Start a webserver on an OS-chosen port serving the `docs` directory. * @returns A promise that resolves once the server is started.

* `_onChange` handles the `change` event. The event’s * target is the heading that has been instructed to expand by click, * keyboard input.

* `_onClick` is the event handler for a click. A click toggles the expanded * and the collapsed state.

* `_onClick()` handles clicks inside the tab panel.

* If the user clicks inside of the `HowtoRadioGroup`, verify that the * clicked element has a `role` of `radio`, and if so, make it the new

* `_onKeyDown` handles key presses inside the accordion.

* `_onKeyDown()` handles key presses inside the tab panel.

* If the user pressed an arrow key, call preventDefault to prevent the * page from scrolling. If the up or left arrow keys were pressed, select

* `_onSlotChange()` is called whenever an element is added or removed from * one of the shadow DOM slots.