code: def slug(self):
      if self._slug is None:
          class_key = (
              f"{self.__class__.__name__.upper()}_REGEX_SUBSTITUTIONS"
          )
          regex_subs = self.settings.get(
              class_key,
              self.settings.get("SLUG_REGEX_SUBSTITUTIONS", []),
          )
          preserve_case = self.settings.get(
              "SLUGIFY_PRESERVE_CASE", False
          )
          self._slug = slugify(
              self.name,
              regex_subs=regex_subs,
              preserve_case=preserve_case,
              use_unicode=self.settings.get(
                  "SLUGIFY_USE_UNICODE", False
              ),
          )
      return self._slug
  
imports: import functools
  import logging
  import os
  import pathlib
  from pelican.utils import slugify
label_desc: Use image node_id 4 for calling the URLWrapper obj's underlying member method code with example usage: obj.slug() and returns: self