docs: def _from_dict(cls, _dict):
          """Initialize a Features object from a json dictionary."""
          args = {}
          if 'concepts' in _dict:
              args['concepts'] = ConceptsOptions._from_dict(_dict.get('concepts'))
          if 'emotion' in _dict:
              args['emotion'] = EmotionOptions._from_dict(_dict.get('emotion'))
          if 'entities' in _dict:
              args['entities'] = EntitiesOptions._from_dict(_dict.get('entities'))
          if 'keywords' in _dict:
              args['keywords'] = KeywordsOptions._from_dict(_dict.get('keywords'))
          if 'metadata' in _dict:
              args['metadata'] = MetadataOptions._from_dict(_dict.get('metadata'))
          if 'relations' in _dict:
              args['relations'] = RelationsOptions._from_dict(
                  _dict.get('relations'))
          if 'semantic_roles' in _dict:
              args['semantic_roles'] = SemanticRolesOptions._from_dict(
                  _dict.get('semantic_roles'))
          if 'sentiment' in _dict:
              args['sentiment'] = SentimentOptions._from_dict(
                  _dict.get('sentiment'))
          if 'categories' in _dict:
              args['categories'] = CategoriesOptions._from_dict(
                  _dict.get('categories'))
          if 'syntax' in _dict:
              args['syntax'] = SyntaxOptions._from_dict(_dict.get('syntax'))
          return cls(**args)