What does "encodings.update(...)" do?

I’m working thru the Question Answering with SQuAD 2.0 module.

I’m stuck in this function:

def add_token_positions(encodings, answers):
    start_positions = []
    end_positions = []
    for i in range(len(answers)):
        start_positions.append(encodings.char_to_token(i, answers[i]['answer_start']))
        end_positions.append(encodings.char_to_token(i, answers[i]['answer_end'] - 1))

        # if start position is None, the answer passage has been truncated
        if start_positions[-1] is None:
            start_positions[-1] = tokenizer.model_max_length
        if end_positions[-1] is None:
            end_positions[-1] = tokenizer.model_max_length

    encodings.update({'start_positions': start_positions, 'end_positions': end_positions})

add_token_positions(train_encodings, train_answers)
add_token_positions(val_encodings, val_answers)

and wondering what
encodings.update({'start_positions': start_positions, 'end_positions': end_positions})
is actualing doing.
I don’t find documentation or helpful information for this. Is there any information available?
And how can I see the result of this function?

Thanks in advance!

This is a Python method for any dictionary, it adds the content of the dictionary passed (so here the "start_positions" and "end_positions") to the encodings.