Make skinparam local to package

[midenok]

Reproduce 1

@startuml
package legend #GreenYellow/LightGoldenRodYellow {
skinparam classBackgroundColor Wheat|CornflowerBlue
A +- B
}
skinparam classBackgroundColor Yellow
C ^- D
@enduml

Result 1

Reproduce 2

@startuml
skinparam classBackgroundColor Yellow
package legend #GreenYellow/LightGoldenRodYellow {
skinparam classBackgroundColor Wheat|CornflowerBlue
A +- B
}
C ^- D
@enduml

Result 2

Expected

In both above cases A and B are Wheat|CornflowerBlue but C and D are Yellow.

[arnaudroques]

Unfortunately, this is very difficult to change using current implementation.
Skinparams are really global to the whole diagram.
Let us think about this...