boolean singleMethodCall() {
          int callCount = 0;
          for (int i = 0; i < graph.transitions.length; i++) {
            if (isMethodCall(graph.methodNode.instructions.get(i).getOpcode())) {
              callCount++;
              if (callCount > 1) {
                return false;
              }
            }
          }
          return callCount == 1;
        }
boolean singleMethodCall()