code: def adjust_for_custom_base_image(self):
          
          plugins = []
          if self.is_custom_base_image():
              # Plugins irrelevant to building base images.
              plugins.append(("prebuild_plugins", "pull_base_image"))
              plugins.append(("prebuild_plugins", "koji_parent"))
              plugins.append(("prebuild_plugins", "inject_parent_image"))
              msg = "removing %s from custom image build request"
          else:
              # Plugins not needed for building non base images.
              plugins.append(("prebuild_plugins", "add_filesystem"))
              msg = "removing %s from non custom image build request"
  
          for when, which in plugins:
              logger.info(msg, which)
              self.dj.remove_plugin(when, which)
docs: Disable plugins to handle builds depending on whether
          or not this is a build from a custom base image.