code: def time_onenormest(self, n, solver):
      if solver == "exact":
          # Get the exact values of one-norms of squares.
          for M in self.matrices:
              M.dot(M)
              scipy.sparse.linalg._matfuncs._onenorm(M)
      elif solver == "onenormest":
          # Get the estimates of one-norms of squares.
          for M in self.matrices:
              scipy.sparse.linalg._matfuncs._onenormest_matrix_power(
                  M, 2
              )
  
imports: import numpy
  from .common import Benchmark, safe_import
label_desc: Use image node_id 2 for calling the BenchmarkOneNormEst obj's underlying member method code with example usage: obj.time_onenormest(n, solver) without return types