code: def comma_list(cls, string):
          '''Convert a comma separated string to list.'''
          items = string.split(',')
          items = list([item.strip() for item in items])
          return itemf comma_list(cls, string):
          '''Convert a comma separated string to list.'''
          items = string.split(',')
          items = list([item.strip() for item in items])
          return items
docs: Convert a comma separated string to list.