code: void insertBackwardEdge(final ManagementEdge managementEdge, final int index) {
  
  		while (index >= this.backwardEdges.size()) {
  			this.backwardEdges.add(null);
  		}
  
  		this.backwardEdges.set(index, managementEdge);
  	}
docs: Adds a new edge which arrives at this gate.
  
  @param managementEdge
  the edge to be added
  @param index
  the index at which the edge shall be added