human
Complete the below
def _bidirectional_pred_succ(G, source, target, ignore_nodes=None, ignore_edges=None):

    ''''Bidirectional shortest path helper.
    Returns (pred,succ,w) where
    pred is a dictionary of predecessors from w to the source, and
    succ is a dictionary of successors from w to the target.'
    '''

=====
Write me a the Python code you requested?
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#Here is the Python code you requested.
    if (target == source):
        return ({target: None}, {source: None}, source)
    if G.is_directed():
        Gpred = G.predecessors
        Gsucc = G.successors
    else:
        Gpred = G.neighbors
        Gsucc = G.neighbors
    if ignore_nodes:
        def filter_iter(nodes):
            def iterate(v):
                for w in nodes(v):
                    if (w not in ignore_nodes):
                        (yield w)
            return iterate
        Gpred = filter_iter(Gpred)
        Gsucc = filter_iter(Gsucc)
    if ignore_edges:
        if G.is_directed():
            def filter_pred_iter(pred_iter):
                def iterate(v):
                    for w in pred_iter(v):
                        if ((w, v) not in ignore_edges):
                            (yield w)
                return iterate
            def filter_succ_iter(succ_iter):
                def iterate(v):
                    for w in succ_iter(v):
                        if ((v, w) not in ignore_edges):
                            (yield w)
                return iterate
            Gpred = filter_pred_iter(Gpred)
            Gsucc = filter_succ_iter(Gsucc)
        else:
            def filter_iter(nodes):
                def iterate(v):
                    for w in nodes(v):
                        if (((v, w) not in ignore_edges) and ((w, v) not in ignore_edges)):
                            (yield w)
                return iterate
            Gpred = filter_iter(Gpred)
            Gsucc = filter_iter(Gsucc)
    pred = {source: None}
    succ = {target: None}
    forward_fringe = [source]
    reverse_fringe = [target]
    while (forward_fringe and reverse_fringe):
        if (len(forward_fringe) <= len(reverse_fringe)):
            this_level = forward_fringe
            forward_fringe = []
            for v in this_level:
                for w in Gsucc(v):
                    if (w not in pred):
                        forward_fringe.append(w)
                        pred[w] = v
                    if (w in succ):
          ...