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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 _probe_adjacency_list(probe):
 """Return an adjacency list of a whole probe."""

    cgs = probe['channel_groups'].values()
    graphs = [cg['graph'] for cg in cgs]
    edges = list(itertools.chain(*graphs))
    adjacency_list = _edges_to_adjacency_list(edges)
    return adjacency_list