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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 _smoothing(precision_fractions, c=1):
 """Compute the smoothed precision for all the orders. Parameters precision_fractions: list(tuple) Contain a list of (precision_numerator, precision_denominator) pairs c: int, default 1 Smoothing constant to use Returns ------- ratios: list of floats Contain the smoothed precision_fractions. """

    ratios = [0] * len(precision_fractions)
    for i, precision_fraction in enumerate(precision_fractions):
        if precision_fraction[1] > 0:
            ratios[i] = float(precision_fraction[0] + c) / (precision_fraction[1] + c)
        else:
            ratios[i] = 0.0

    return ratios