code: def load_combo_catalog():
      
      user_dir = user_data_dir()
      global_dir = global_data_dir()
      desc = 'Generated from data packages found on your intake search path'
      cat_dirs = []
      if os.path.isdir(user_dir):
          cat_dirs.append(user_dir + '/*.yaml')
          cat_dirs.append(user_dir + '/*.yml')
      if os.path.isdir(global_dir):
          cat_dirs.append(global_dir + '/*.yaml')
          cat_dirs.append(global_dir + '/*.yml')
      for path_dir in conf.get('catalog_path', []):
          if path_dir != '':
              if not path_dir.endswith(('yaml', 'yml')):
                  cat_dirs.append(path_dir + '/*.yaml')
                  cat_dirs.append(path_dir + '/*.yml')
              else:
                  cat_dirs.append(path_dir)
  
      return YAMLFilesCatalog(cat_dirs, name='builtin', description=desc)
docs: Load a union of the user and global catalogs for convenience