Note: Types Invoke, ReturnResult,
ReturnError defined in this module have multiple
CONSTRAINED BY subtype constraints, each one containing an
exception marker (symbol "!"). Implementors of ITU-T Rec. X.880
are warned to the following rule of the ASN.1 standard: Where a type
is constrained by multiple constraints, more than one of which has an
exception identifier, the exception identifier in the outermost
constraint shall be regarded as the exception identifier for that
type (see ITU-T Rec. X.680:2002, 49.5).