class Node:
    def __init__(self, val):
        self.val = val
        self.next = None

def eraseAll(head, x):
    dummy = Node(0)
    dummy.next = head
    cur = dummy

    while cur.next:
        if cur.next.val == x:
            ____________________ # 填空处
        else:
            cur = cur.next

    return dummy.next