class SinglyLinkedList:
    #constructor
    def __init__(self):
        self.head = None

    #method for setting the head of the Linked List
    def setHead(self,head):
        self.head = head

    #method for deleting a node having a certain data
    #method for deleting a node having a certain data
    def delete(self,data):
        if self.head is None:
            return None
        else:
            cur  = self.head
            prev = None
            while cur.data != data and cur.next is not None:
                prev = cur
                cur = cur.next

            # when found
            if cur.data == data:
                # if head
                if cur == self.head:
                    if cur.next is None:
                        self.head = None
                    else:
                        self.head = cur.next
                else:
                    if cur.next is None:
                        prev.next = None
                    else:
                        prev.next = cur.next
            else:
                return None