code: def get_consensus_module(module_name):
          
          module_package = module_name
          if module_name == 'genesis':
              module_package = (
                  'sawtooth_validator.journal.consensus.genesis.'
                  'genesis_consensus'
              )
          elif module_name == 'devmode':
              module_package = (
                  'sawtooth_validator.journal.consensus.dev_mode.'
                  'dev_mode_consensus'
              )
  
          try:
              return importlib.import_module(module_package)
          except ImportError:
              raise UnknownConsensusModuleError(
                  'Consensus module "{}" does not exist.'.format(module_name))
docs: Returns a consensus module by name.
  
          Args:
              module_name (str): The name of the module to load.
  
          Returns:
              module: The consensus module.
  
          Raises:
              UnknownConsensusModuleError: Raised if the given module_name does
                  not correspond to a consensus implementation.