def modify_instance_placement(InstanceId=None, Tenancy=None, Affinity=None,
    HostId=None):
    """
    Set the instance affinity value for a specific stopped instance and modify the instance tenancy setting.
    Instance affinity is disabled by default. When instance affinity is host and it is not associated with a specific Dedicated Host, the next time it is launched it will automatically be associated with the host it lands on. This relationship will persist if the instance is stopped/started, or rebooted.
    You can modify the host ID associated with a stopped instance. If a stopped instance has a new host ID association, the instance will target that host when restarted.
    You can modify the tenancy of a stopped instance with a tenancy of host or dedicated .
    Affinity, hostID, and tenancy are not required parameters, but at least one of them must be specified in the request. Affinity and tenancy can be modified in the same request, but tenancy can only be modified on instances that are stopped.
    See also: AWS API Documentation
    
    
    :example: response = client.modify_instance_placement(
        InstanceId='string',
        Tenancy='dedicated'|'host',
        Affinity='default'|'host',
        HostId='string'
    )
    
    
    :type InstanceId: string
    :param InstanceId: [REQUIRED]
            The ID of the instance that you are modifying.
            

    :type Tenancy: string
    :param Tenancy: The tenancy of the instance that you are modifying.

    :type Affinity: string
    :param Affinity: The new affinity setting for the instance.

    :type HostId: string
    :param HostId: The ID of the Dedicated Host that the instance will have affinity with.

    :rtype: dict
    :return: {
        'Return': True|False
    }
    
    
    """
    pass
