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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 _distance_covariance_sqr_naive(x, y, exponent=1):
 """ Naive biased estimator for distance covariance. Computes the unbiased estimator for distance covariance between two matrices, using an :math:`O(N^2)` algorithm. """

    a = _distance_matrix(x, exponent=exponent)
    b = _distance_matrix(y, exponent=exponent)

    return mean_product(a, b)