code: def set_flair_csv(self, subreddit, flair_mapping):
          
          if not flair_mapping:
              raise errors.ClientException('flair_mapping must be set')
          item_order = ['user', 'flair_text', 'flair_css_class']
          lines = []
          for mapping in flair_mapping:
              if 'user' not in mapping:
                  raise errors.ClientException('flair_mapping must '
                                               'contain `user` key')
              lines.append(','.join([mapping.get(x, '') for x in item_order]))
          response = []
          while len(lines):
              data = {'r': six.text_type(subreddit),
                      'flair_csv': '\n'.join(lines[:100])}
              response.extend(self.request_json(self.config['flaircsv'],
                                                data=data))
              lines = lines[100:]
          evict = self.config['flairlist'].format(
              subreddit=six.text_type(subreddit))
          self.evict(evict)
          return response
docs: Set flair for a group of users in the given subreddit.
  
          flair_mapping should be a list of dictionaries with the following keys:
            `user`: the user name,
            `flair_text`: the flair text for the user (optional),
            `flair_css_class`: the flair css class for the user (optional)
  
          :returns: The json response from the server.