datetime

1. Current date and time datetime now
2. Converting string to datetime (parsing date and time string)
3. Parse datetime string with and without timezone information
4. datetime fromisoformat
5. date fromisoformat (only date, no time)
6. datetime arithmeticis (subtract)
7. Timezone aware datetime
8. datetime arithmeticis (compare, sort)
9. datetime arithmeticis (addition)
10. Rounding datetime object to nearest second (removing microseconds)
11. Rounding datetime object to date (removing hours, minutes, seconds)
12. Convert datetime object to date object
13. Convert datetime object to time object
14. Today (date)