docs: def drug_name_to_generic(drug_name: str,
                           unknown_to_default: bool = False,
                           default: str = None,
                           include_categories: bool = False) -> str:
      """
      Converts a drug name to the name of its generic equivalent.
      """
      drug = get_drug(drug_name, include_categories=include_categories)
      if drug is not None:
          return drug.generic_name
      return default if unknown_to_default else drug_name