def METHOD_NAME(api_name: Optional[pulumi.Input[str]] = None,
                          resource_group_name: Optional[pulumi.Input[str]] = None,
                          subscription_id: Optional[pulumi.Input[Optional[str]]] = None,
                          opts: Optional[pulumi.InvokeOptions] = None) -> pulumi.Output[GetCustomApiResult]:
    """
    Gets a custom API by name for a specific subscription and resource group
    :param str api_name: API name
    :param str resource_group_name: The resource group
    :param str subscription_id: Subscription Id
    """
    ...