@mock.patch.multiple(
      systemconfig, SCPreferencesCreate=mock.DEFAULT,
      SCPreferencesCommitChanges=mock.DEFAULT)
  def testSaveCommitFailed(self, **mocks):
    mocks['SCPreferencesCreate'].return_value = 'session'
    mocks['SCPreferencesCommitChanges'].return_value = False
    scp = systemconfig.SCPreferences()
    self.assertRaises(systemconfig.SysconfigError, scp.Save)
Stream the block header in the standard way to the file-like object f.
dataset/ETHPy150Open google/macops/gmacpyutil/gmacpyutil/systemconfig_test.py/SCPreferencesTest.testSaveCommitFailed--crossover with--dataset/ETHPy150Open maraoz/proofofexistence/pycoin/block.py/BlockHeader.stream