Python 遍历嵌套字典

首先，这里是问题和编写的代码:

def family_lineage(familytree, lineage): 
    '''(dict, list of strs) -> boolean 
    Return True if lineage specifies a list of names who are directly related 
    in a chain of parent-child relationships, and NOT child-parent, parent-grandchild..etc, 
    beginning from the first generation listed. 
 
    >>> trace_lineage({'Gina': {'Sam': {'Tina': {}}, 
                           'Li': {}}, 
                   'Guy': {}}, 
                      ['Gina']) 
    True 
 
    >>> trace_lineage({'Gina': {'Sam': {'Tina': {}}, 
                               'Li': {}}, 
                       'Guy': {}}, 
                      ['Gina', 'Sam', 'Tina']) 
    True 
    >>> trace_lineage({'Gina': {'Sam': {'Tina': {}}, 
                               'Li': {}}, 
                       'Guy': {}}, 
                      ['Gina', 'Tina']) 
    False 
    ''' 

因此，在上面的示例中，它显示“Guy”没有 child ，而“Gina”有两个 child ，“Sam”和“Li”。 “山姆”有一个 child ，“蒂娜”。

for k, v in familytree.items(): 
    for n, m in v.items(): 
        if lineage[0] == any(k) and len(lineage) == 1: 
            return True 
        elif lineage[0] == k and lineage[1] == n and len(lineage) ==2: 
            return True 
        elif lineage[0] == k and lineage[1] == n and lineage[2] == m and \ 
        len(lineage) == 3: 
            return True 
        else: 
            return False 

所以，我的问题是，如果家谱超过三代，我该怎么写？有没有更简洁的方式来编写这段代码？

请您参考如下方法:

这是一种迭代方法，即使 lineage 不是从家谱树的顶部开始也是有效的:

def family_lineage(familytree, lineage): 
    trees = [familytree] 
    while trees: 
        tree = trees.pop() 
        trees.extend(t for t in tree.values() if t) 
        for name in lineage: 
            if name not in tree: 
                break 
            tree = tree[name] 
        else: 
            return True 
    return False