6. bool remove_before(int item) deletes the node just before the node containing "item" in the SinglyLinkedlist. It should return true for a successful operation, and false for an unsuccessful operation. For example, Explanation 15, which comes before 20, is deleted. Sample input Sample output Linkedlist:->10->15->20->25->30-> Returns true remove_before(20); Linkedlist:->10->20->25->30-> Linkedlist:->10->20->25->30-> Returns false remove_before(40); Linkedlist:->10->20->25->30-> Linkedlist:->10->20->25->30-> Returns false remove_before(10); Linkedlist:->10->20->25->30-> 40 is not found, so nothing is deleted. 10 is the first node, so nothing is deleted. The following pseudocode does the trick. remove_before(item) { current = head prev = NULL prevprev = NULL while (current is not NULL) { if (current->data == item) break prevprev = prev prev = current current = current->next } if (current is NULL) return false if (current == head) return false if (prev == head) return remove_first() prevprev->next = current free prev return true Now complete the method in the cpp file. Rigorously test your code with sample test cases