How to use the aiobotocore.session function in aiobotocore

def aiobotocore_client(service, tracer):
    """Helper function that creates a new aiobotocore client so that
    it is closed at the end of the context manager.
    """
    session = aiobotocore.session.get_session()
    endpoint = LOCALSTACK_ENDPOINT_URL[service]
    client = session.create_client(
        service,
        region_name='us-west-2',
        endpoint_url=endpoint,
        aws_access_key_id='aws',
        aws_secret_access_key='aws',
        aws_session_token='aws',
    )
    Pin.override(client, tracer=tracer)
    try:
        yield client
    finally:
        client.close()

def __init__(self, aws_access_key_id=None, aws_secret_access_key=None,
                 aws_session_token=None, region_name=None,
                 botocore_session=None, profile_name=None, loop=None):
        if botocore_session is not None:
            self._session = botocore_session
        else:
            # Create a new default session
            self._session = aiobotocore.session.get_session(loop=loop)

        # Setup custom user-agent string if it isn't already customized
        if self._session.user_agent_name == 'Botocore':
            botocore_info = 'Botocore/{0}'.format(
                self._session.user_agent_version)
            if self._session.user_agent_extra:
                self._session.user_agent_extra += ' ' + botocore_info
            else:
                self._session.user_agent_extra = botocore_info
            self._session.user_agent_name = 'Boto3'
            self._session.user_agent_version = boto3.__version__

        if profile_name is not None:
            self._session.set_config_variable('profile', profile_name)

        if aws_access_key_id or aws_secret_access_key or aws_session_token: