selection.py

    def get_width(self, width):
        """Returns an acceptable width from a requested width.

        Per https://developers.facebook.com/docs/plugins/embedded-posts/, FB
        embeds must be between 350 and 750 pixels wide.

        If no width passed, default to 360, else get as close to requested
        width as possible while following FB's guidelines.
        """
        if not width:
            width = 585
        elif width > 750:
            width = 750
        elif width < 350:
            width = 350

        return width