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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 filter(self, run_counts, criteria):
 """ Return run counts only for examples that are still correctly classified """

    correctness = criteria['correctness']
    assert correctness.dtype == np.bool
    filtered_counts = deep_copy(run_counts)
    for key in filtered_counts:
      filtered_counts[key] = filtered_counts[key][correctness]
    return filtered_counts