Mismatch datatype of consumer_tag in Basic.ConsumeOk

[duynhaaa]

This is how Pika generate consumer tag (line 336 in pika/channel.py):

def _generate_consumer_tag(self):
    """Generate a consumer tag

    NOTE: this protected method may be called by derived classes

    :returns: consumer tag
    :rtype: str

    """
    return 'ctag%i.%s' % (self.channel_number, uuid.uuid4().hex)

By default, the consumer tag is a str, which contradicts the data type of ConsumeOk.consume_tag in the stub file (line 1415 in pika-stubs/spec.pyi):

class ConsumeOk(amqp_object.Method):
    ...
    consumer_tag: Optional[int] = ...
    ...

So, is this an error on pika-stubs?

Disclaimer: I haven't read the AMQP specification. (Edit: I'm reading it, but not thoroughly)