docs: def from_config(cls, config, name, section_key="segmenters"):
          """
          Constructs a segmenter from a configuration doc.
          """
          section = config[section_key][name]
          segmenter_class_path = section['class']
          Segmenter = yamlconf.import_module(segmenter_class_path)
          return Segmenter.from_config(config, name, section_key=section_key)