def METHOD_NAME():
    ec2 = boto3.client("ec2", region_name="us-west-1")
    gateway_id1 = ec2.create_transit_gateway(Description="my first gateway")[
        "TransitGateway"
    ]["TransitGatewayId"]
    gateway_id2 = ec2.create_transit_gateway(Description="my second gateway")[
        "TransitGateway"
    ]["TransitGatewayId"]
    attchment_id = create_peering_attachment(ec2, gateway_id1, gateway_id2)
    ec2.accept_transit_gateway_peering_attachment(
        TransitGatewayAttachmentId=attchment_id
    )
    attachment = ec2.describe_transit_gateway_peering_attachments(
        TransitGatewayAttachmentIds=[attchment_id]
    )["TransitGatewayPeeringAttachments"][0]
    assert attachment["TransitGatewayAttachmentId"] == attchment_id
    assert attachment["State"] == "available"