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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 detect_best_flux_limit(model):
 """Detect the best default flux limit to use for model output. The default flux limit does not change the model but selecting a good value reduced the amount of output produced and reduces clutter in the output files. """

    flux_limit_count = Counter()

    for reaction in model.reactions:
        if reaction.id not in model.limits:
            continue

        equation = reaction.properties['equation']
        if equation is None:
            continue

        _, lower, upper = model.limits[reaction.id]
        if upper is not None and upper > 0 and equation.direction.forward:
            flux_limit_count[upper] += 1
        if lower is not None and -lower > 0 and equation.direction.reverse:
            flux_limit_count[-lower] += 1

    if len(flux_limit_count) == 0:
        return None

    best_flux_limit, _ = flux_limit_count.most_common(1)[0]
    return best_flux_limit