def find_bidi(self, el):
        """Get directionality from element text."""

        for node in self.get_children(el, tags=False):

            # Analyze child text nodes
            if self.is_tag(node):

                # Avoid analyzing certain elements specified in the specification.
                direction = DIR_MAP.get(util.lower(self.get_attribute_by_name(node, 'dir', '')), None)
                if (
                    self.get_tag(node) in ('bdi', 'script', 'style', 'textarea', 'iframe') or
                    not self.is_html_tag(node) or
                    direction is not None
                ):
                    continue  # pragma: no cover

                # Check directionality of this node's text
                value = self.find_bidi(node)
                if value is not None:
                    return value

                # Direction could not be determined
                continue  # pragma: no cover

            # Skip `doctype` comments, etc.
            if self.is_special_string(node):
                continue

            # Analyze text nodes for directionality.
            for c in node:
                bidi = unicodedata.bidirectional(c)
                if bidi in ('AL', 'R', 'L'):
                    return ct.SEL_DIR_LTR if bidi == 'L' else ct.SEL_DIR_RTL
        return None
Get directionality from element text.