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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def matrix_to_listlist(weight):
 """transforms a squared weight matrix in a adjacency table of type listlist encoding the directed graph corresponding to the entries of the matrix different from None :param weight: squared weight matrix, weight[u][v] != None iff arc (u,v) exists :complexity: linear :returns: the unweighted directed graph in the listlist representation, listlist[u] contains all v for which arc (u,v) exists. """

    graph = [[] for _ in range(len(weight))]
    for u in range(len(graph)):
        for v in range(len(graph)):
            if weight[u][v] != None:
                graph[u].append(v)
    return graph