std::chrono::year_month::year, std::chrono::year_month::month
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                    < cpp | chrono | year month
                    
                                                            
                    |   constexpr std::chrono::year year() const noexcept;  | 
(1) | (since C++20) | 
|   constexpr std::chrono::month month() const noexcept;  | 
(2) | (since C++20) | 
Retrieves the year and month values stored in this year_month object.
Return values
1) Returns the stored std::chrono::year value.
2) Returns the stored std::chrono::month value.