58                 return std::nullopt;  in fromDurationString()
78             return std::nullopt;  in fromDurationString()
84             return std::nullopt;  in fromDurationString()
90                 return std::nullopt;  in fromDurationString()
98                 return std::nullopt;  in fromDurationString()
106                 return std::nullopt;  in fromDurationString()
114                 return std::nullopt;  in fromDurationString()
131                 return std::nullopt;  in fromDurationString()
153             return std::nullopt;  in fromDurationString()
215         return std::nullopt;  in toDurationStringFromUint()
221         return std::nullopt;  in toDurationStringFromUint()
462         return std::nullopt;  in getDateTimeIso8601()
502                 return std::nullopt;  in dateStringToEpoch()
512     return std::nullopt;  in dateStringToEpoch()