+ void remove_successor(ActivityPtr a)
+ {
+ if(this == a)
+ throw std::invalid_argument("Cannot ask to remove its from successors");
+
+ auto p = std::find_if(successors_.begin(), successors_.end(), [a](ActivityPtr const& i){ return i.get() == a.get(); });
+ if (p != successors_.end()){
+ successors_.erase(p);
+ a->dependencies_.erase({this});
+ } else
+ throw std::invalid_argument("Dependency does not exist. Can not be removed.");
+ }
+