sunrise property Null safety

1. weather
2. open_weather
3. Sys
4. sunrise property

Sys class

1. Constructors
2. Sys
3. fromJson
4. Properties
5. country
6. hashCode
7. id
8. runtimeType
9. sunrise
10. sunset
11. type
12. Methods
13. noSuchMethod
14. toJson
15. toString
16. Operators
17. operator ==