docs: def get_ref_data_map(self, bulk_mode=True):
          """
          Get referential data from the local db into the self.ref_data_map dictionary.
          This allows for fast FK lookups when looping through posts.
  
          :param bulk_mode: if True, actually get all of the existing ref data
                            else this would be too much memory, so just build empty dicts
          :return: None
          """
          if bulk_mode:
              self.ref_data_map = {
                  "authors": {a.wp_id: a for a in Author.objects.filter(site_id=self.site_id)},
                  "categories": {c.wp_id: c for c in Category.objects.filter(site_id=self.site_id)},
                  "tags": {t.wp_id: t for t in Tag.objects.filter(site_id=self.site_id)},
                  "media": {m.wp_id: m for m in Media.objects.filter(site_id=self.site_id)}
              }
          else:
              # in single post mode, WP ref data is handled dynamically for the post
              self.ref_data_map = {
                  "authors": {},
                  "categories": {},
                  "tags": {},
                  "media": {}
              }