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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 lorenz(values, weights = None):
 """ Computes Lorenz Curve coordinates """

    if weights is None:
        weights = ones(len(values))

    df = pd.DataFrame({'v': values, 'w': weights})
    df = df.sort_values(by = 'v')
    x = cumsum(df['w'])
    x = x / float(x[-1:])
    y = cumsum(df['v'] * df['w'])
    y = y / float(y[-1:])

    return x, y