Return a DatetimeInterval object whose value is the sum of the specified lhs and rhs time intervals. The behavior is undefined unless the resulting time interval value is valid (i.e., the days field must not overflow a 32-bit integer).
Declared in <bdlt_datetimeinterval.h>
bdlt::DatetimeInterval
operator+(
DatetimeInterval const& lhs,
DatetimeInterval const& rhs);