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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 show_instance(name, call=None):
    '''
    List the a single node, return dict of grains.
    '''
    local = salt.client.LocalClient()
    ret = local.cmd(name, 'grains.items')
    ret.update(_build_required_items(ret))
    return ret