docs: def _from_dict(cls, _dict):
          """Initialize a CompareReturn object from a json dictionary."""
          args = {}
          if 'model_id' in _dict:
              args['model_id'] = _dict.get('model_id')
          if 'model_version' in _dict:
              args['model_version'] = _dict.get('model_version')
          if 'documents' in _dict:
              args['documents'] = [
                  Document._from_dict(x) for x in (_dict.get('documents'))
              ]
          if 'aligned_elements' in _dict:
              args['aligned_elements'] = [
                  AlignedElement._from_dict(x)
                  for x in (_dict.get('aligned_elements'))
              ]
          if 'unaligned_elements' in _dict:
              args['unaligned_elements'] = [
                  UnalignedElement._from_dict(x)
                  for x in (_dict.get('unaligned_elements'))
              ]
          return cls(**args)