code: def _default_label(self, base, context, **kwargs):
          
  
          kwargs['context'] = context
          params = len(getattr(self.filter(check_visible=False,**kwargs), '{}s'.format(context)))
  
          return "{}{:02d}".format(base, params+1)
docs: Determine a default label given a base label and the passed kwargs
  
          this simply counts the current number of matches on metawargs and
          appends that number to the base
  
          :parameter str base: the base string for the label
          :parameter str context: name of the context (where the label is going)
          :parameter **kwargs: the kwargs to run a filter on.  The returned label
              will be "{}{:02d}".format(base, number_of_results_with_kwargs+1)
          :return: label