std::chrono::month_weekday_last::month_weekday_last
From cppreference.com
                    
                                        
                    < cpp | chrono | month weekday last
                    
                                                            
                    |   constexpr month_weekday_last( const std::chrono::month& m, const std::chrono::weekday_last& wdl ) noexcept;  | 
(since C++20) | |
Constructs a month_weekday_last object that stores the month m and the weekday_last wdl.
Notes
A more convenient way to construct a month_weekday_last is with operator/, e.g., std::chrono::April/std::chrono::Sunday[std::chrono::last].
See also
|    (C++20)  | 
  conventional syntax for Gregorian calendar date creation  (function)  |