SimpleAttribute Natural {}
SimpleAttribute String {}

Class Place {
    name = "Place"
    tokens : Natural
    name : String
}
Class Transition {
    name = "Transition"
    name : String
}
Association P2T (Place, Transition) {
    name = "P2T"
    weight : Natural
}
Association T2P (Transition, Place) {
    name = "T2P"
    weight : Natural
}