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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 get_consensus_module(module_name):
 """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. """

        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))