code: private boolean isCallingOnThis(String sig) {
          if (getMethod().isStatic()) {
              return false;
          }
  
          int numParameters = SignatureUtils.getNumParameters(sig);
          if (stack.getStackDepth() <= numParameters) {
              return false;
          }
  
          OpcodeStack.Item item = stack.getStackItem(numParameters);
          return item.getRegisterNumber() == 0;
      }
docs: checks to see if an instance method is called on the 'this' object
  
  @param sig
  the signature of the method called to find the called-on object
  @return when it is called on this or not