docs: def sparse_mean_var(data):
      """
      Calculates the variance for each row of a sparse matrix,
      using the relationship Var = E[x^2] - E[x]^2.
  
      Returns:
          pair of matrices mean, variance.
      """
      data = sparse.csc_matrix(data)
      return sparse_means_var_csc(data.data,
              data.indices,
              data.indptr,
              data.shape[1],
              data.shape[0])