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