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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 false_negatives(links_true, links_pred):
 """Count the number of False Negatives. Returns the number of incorrect predictions of true links. (true links, but predicted as non-links). This value is known as the number of False Negatives (FN). Parameters links_true: pandas.MultiIndex, pandas.DataFrame, pandas.Series The true (or actual) links. links_pred: pandas.MultiIndex, pandas.DataFrame, pandas.Series The predicted links. Returns ------- int The number of false negatives. """


    links_true = _get_multiindex(links_true)
    links_pred = _get_multiindex(links_pred)

    return len(links_true.difference(links_pred))