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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 auth(nodes, pcsuser='hacluster', pcspasswd='hacluster', extra_args=None):
    '''
    Authorize nodes to the cluster

    nodes
        a list of nodes which should be authorized to the cluster
    pcsuser
        user for communitcation with PCS (default: hacluster)
    pcspasswd
        password for pcsuser (default: hacluster)
    extra_args
        list of extra option for the \'pcs cluster auth\' command

    CLI Example:

    .. code-block:: bash

        salt '*' pcs.auth nodes='[ node1.example.org node2.example.org ]' pcsuser=hacluster pcspasswd=hoonetorg extra_args="[ '--force' ]"
    '''
    cmd = ['pcs', 'cluster', 'auth']

    if pcsuser:
        cmd += ['-u', pcsuser]

    if pcspasswd:
        cmd += ['-p', pcspasswd]

    if isinstance(extra_args, (list, tuple)):
        cmd += extra_args
    cmd += nodes

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