docs: def _from_dict(cls, _dict):
          """Initialize a DocStructure object from a json dictionary."""
          args = {}
          if 'section_titles' in _dict:
              args['section_titles'] = [
                  SectionTitles._from_dict(x)
                  for x in (_dict.get('section_titles'))
              ]
          if 'leading_sentences' in _dict:
              args['leading_sentences'] = [
                  LeadingSentence._from_dict(x)
                  for x in (_dict.get('leading_sentences'))
              ]
          return cls(**args)