code: public List<IntVar> getOutgoing(Node n) {
          List<IntVar> l = outgoings.get(n);
          if (l == null) {
              l = Collections.emptyList();
          }
          return l;
  
      }
docs: Get the start moment of the movements that leave
  from a given node
  
  @param n the source node
  @return a list of start moment. May be empty