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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 _fD(self, neg_pairs, A):
 """The value of the dissimilarity constraint function. f = f(\sum_{ij \in D} distance(x_i, x_j)) i.e. distance can be L1: \sqrt{(x_i-x_j)A(x_i-x_j)'} """

    diff = neg_pairs[:, 0, :] - neg_pairs[:, 1, :]
    return np.log(np.sum(np.sqrt(np.sum(np.dot(diff, A) * diff, axis=1))) + 1e-6)