def copyRandomList(self, head):
from collections import defaultdict
d = defaultdict(lambda: RandomListNode(0))
d[None] = None
m = head
while m :
d[m].label = m.label
d[m].next = d[m.next]
d[m].random = d[m.random]
m = m.next
return d[head]
Please comment your thoughts and explain the above, since I have found it on the internet somewhere.