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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 cluster_node_add(node, extra_args=None):
    '''
    Add a node to the pacemaker cluster via pcs command

    node
        node that should be added
    extra_args
        list of extra option for the \'pcs cluster node add\' command

    CLI Example:

    .. code-block:: bash

        salt '*' pcs.cluster_node_add node=node2.example.org
    '''
    cmd = ['pcs', 'cluster', 'node', 'add']

    cmd += [node]
    if isinstance(extra_args, (list, tuple)):
        cmd += extra_args

    return __salt__['cmd.run_all'](cmd, output_loglevel='trace', python_shell=False)