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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 convertToRateMatrix(self, Q):
 """ Converts the initial matrix to a rate matrix. We make all rows in Q sum to zero by subtracting the row sums from the diagonal. """

        rowSums             = Q.sum(axis=1).getA1()
        idxRange            = np.arange(Q.shape[0])
        Qdiag               = coo_matrix((rowSums,(idxRange,idxRange)),shape=Q.shape).tocsr()
        return Q-Qdiag