std::chrono::month::month
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | month() = default; | (1) | (since C++20) | 
| explicit constexpr month(unsigned m) noexcept; | (2) | (since C++20) | 
Constructs a month object.
1) Default constructor leaves the month value uninitialized.
2) If m <= 255, constructs a 
month object holding the month value m. Otherwise the value held is unspecified.