.MessageError: ClassType
.MessageError <: Exception

.MessageParseError: ClassType
.MessageParseError <: MessageError

.HeaderParseError: ClassType
.HeaderParseError <: MessageParseError

.BoundaryError: ClassType
.BoundaryError <: MessageParseError

.MultipartConversionError: ClassType
.MultipartConversionError <: MessageError

.CharsetError: ClassType
.CharsetError <: MessageError

.MessageDefect: ClassType
.MessageDefect <: ValueError

.NoBoundaryInMultipartDefect: ClassType
.NoBoundaryInMultipartDefect <: MessageDefect

.StartBoundaryNotFoundDefect: ClassType
.StartBoundaryNotFoundDefect <: MessageDefect

.ClosedBoundaryNotFoundDefect: ClassType
.ClosedBoundaryNotFoundDefect <: MessageDefect

.FirstHeaderLineIsContinuationDefect: ClassType
.FirstHeaderLineIsContinuationDefect <: MessageDefect

.MisplacedEnvelopeHeaderDefect: ClassType
.MisplacedEnvelopeHeaderDefect <: MessageDefect

.MultipartInvariantViolationDefect: ClassType
.MultipartInvariantViolationDefect <: MessageDefect

.InvalidMultipartContentTransferEncodingDefect: ClassType
.InvalidMultipartContentTransferEncodingDefect <: MessageDefect

.UndecodableBytesDefect: ClassType
.UndecodableBytesDefect <: MessageDefect

.InvalidBase64PaddingDefect: ClassType
.InvalidBase64PaddingDefect <: MessageDefect

.InvalidBase64CharactersDefect: ClassType
.InvalidBase64CharactersDefect <: MessageDefect

.InvalidBase64LengthDefect: ClassType
.InvalidBase64LengthDefect <: MessageDefect

.HeaderDefect: ClassType
.HeaderDefect <: MessageDefect

.InvalidHeaderDefect: ClassType
.InvalidHeaderDefect <: HeaderDefect

.HeaderMissingRequiredValue: ClassType
.HeaderMissingRequiredValue <: HeaderDefect

.NonPrintableDefect: ClassType
.NonPrintableDefect <: HeaderDefect

.ObsoleteHeaderDefect: ClassType
.ObsoleteHeaderDefect <: HeaderDefect

.NonASCIILocalPartDefect: ClassType
.NonASCIILocalPartDefect <: HeaderDefect

.InvalidDateDefect: ClassType
.InvalidDateDefect <: HeaderDefect