def benchmark_rank_by_median(benchmark_snapshot_df):
    """Returns ranking of fuzzers based on median coverage."""
    assert benchmark_snapshot_df.time.nunique() == 1, 'Not a snapshot!'
    medians = benchmark_snapshot_df.groupby('fuzzer')['edges_covered'].median()
    medians.rename('median cov', inplace=True)
    return medians.sort_values(ascending=False)