How is an object of type BaseModelOutput subscriptable?

🤗Transformers
1

I have a code where self.encoder is an object of type ViTEncoder. ViTEncoder’s forward method returns an object of type BaseModelOutput.

When I call the forward method of ViTEncoder, I get back an object that is subscriptable, how is this possible?

encoder_outputs = self.encoder(
            embedding_output,
            head_mask=head_mask,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            return_dict=return_dict,
        )
sequence_output = encoder_outputs[0] # how is this subscriptable?
print(f"The encoder output is {encoder_outputs}") # prints the type of object as BaseModelOutput

This is the definition of BaseModelOuput class.