code: def parse_cat_ini_opt(cat_str):
      
      if cat_str == "":
          return []
  
      cat_groups = cat_str.split(',')
      cat_sets = []
      for group in cat_groups:
          group = group.strip()
          cat_sets += [set(c for c in group)]
      return cat_sets
docs: Parse a cat str from the ini file into a list of sets