def find_elements(strategy, locator, root=None):
Finds elements on the page.

        :param strategy: Location strategy to use (type depends on the driver implementation)
        :param locator: Location of target elements.
        :param root: (optional) root node.
        :type strategy: str
        :type locator: str
        :type root: web element object or None.
        :return: iterable of web element objects
        :rtype: iterable (if depends on the driver implementation)