code: def get_icon_url(self, brain):
          
          icon_url = api.get_icon(brain, html_tag=False)
          url, icon = icon_url.rsplit("/", 1)
          relative_url = url.lstrip(self.portal.absolute_url())
          name, ext = os.path.splitext(icon)
  
          # big icons endwith _big
          if not name.endswith("_big"):
              icon = "{}_big{}".format(name, ext)
  
          icon_big_url = "/".join([relative_url, icon])
  
          # fall back to a default icon if the looked up icon does not exist
          if self.context.restrictedTraverse(icon_big_url, None) is None:
              icon_big_url = "++resource++senaite.lims.images/gears.png"
  
          return icon_big_url
docs: Returns the (big) icon URL for the given catalog brain