def METHOD_NAME(domain_name: Optional[pulumi.Input[str]] = None,
                               email_service_name: Optional[pulumi.Input[str]] = None,
                               resource_group_name: Optional[pulumi.Input[str]] = None,
                               sender_username: Optional[pulumi.Input[str]] = None,
                               opts: Optional[pulumi.InvokeOptions] = None) -> pulumi.Output[GetSenderUsernameResult]:
    """
    Get a valid sender username for a domains resource.
    :param str domain_name: The name of the Domains resource.
    :param str email_service_name: The name of the EmailService resource.
    :param str resource_group_name: The name of the resource group. The name is case insensitive.
    :param str sender_username: The valid sender Username.
    """
    ...