code: def add_filter(self, files_filter, filter_type=DefaultFilterType):
          
          self.__filters.append((files_filter, filter_type))
          return self
docs: Add a files filter to this iterator.
          For a file to be processed, it must match ALL filters, eg they are added with ADD, not OR.
  
          :param files_filter: filter to apply, must be an object inheriting from filters.FilterAPI.
          :param filter_type: filter behavior, see FilterType for details.