human
I wrote the below code

    def func(v, k, c):
        return ((c[v] == k) and (k == sum((1 for w in G[v] if (c[w] >= k)))))
    return _core_subgraph(G, func, k, core_number)

What's a good function header?
assistant
#Here's a good function header.

def k_corona(G, k, core_number=None):