python and逻辑

最近刷题遇到快慢指针判断链表是否循环，我的代码为：

class Solution:
    def hasCycle(self, head: Optional[ListNode]) -> bool:
        fast = slow = head
        while fast.next and fast:
            fast = fast.next.next
            slow = slow.next
            
            if fast == slow:
                return True
           
        return False

正确代码为：

class Solution:
    def hasCycle(self, head: Optional[ListNode]) -> bool:
        fast = slow = head
        while fast and fast.next:
            fast = fast.next.next
            slow = slow.next
            
            if fast == slow:
                return True
           
        return False

正当我感觉没什么不同时，突然想到Python与逻辑会先判断前面的，如果前面的不成立，那整个与表达式就不成立。