docs: def extra_configuration_collection(self, configuration):
          """
          Hook to do any extra configuration collection or converter registration
          """
          harpoon_spec = HarpoonSpec()
  
          for image in configuration.get('images', {}).keys():
              self.make_image_converters(image, configuration, harpoon_spec)
  
          self.register_converters(
                { (0, ("content", )): sb.dictof(sb.string_spec(), sb.string_spec())
                , (0, ("harpoon", )): harpoon_spec.harpoon_spec
                , (0, ("authentication", )): harpoon_spec.authentications_spec
                }
              , Meta, configuration, sb.NotSpecified
              )
  
          # Some other code works better when harpoon no existy
          if configuration["harpoon"] is sb.NotSpecified:
              del configuration["harpoon"]