Values_4.ModifyInstanceMetadataDefaultsResultSourceModifies the default instance metadata service (IMDS) settings at the account level in the specified Amazon Web Services
 Region. To remove a parameter's account-level default setting, specify no-preference. If an account-level setting is cleared with no-preference, then the instance launch considers the other instance metadata settings. For more information, see Order of precedence for instance metadata options in the Amazon EC2 User Guide.
type nonrec t = {return : Values_0.Boolean.t option;If the request succeeds, the response returns true. If the request fails, no response is returned, and instead an error message is returned.
*)}val error_of_json :
'a ->
Yojson.Safe.t ->
[> `Unknown_operation_error of 'a * string option ]