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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 _servicegroup_get(sg_name, **connection_args):
    '''
    Return a service group ressource or None
    '''
    nitro = _connect(**connection_args)
    if nitro is None:
        return None
    sg = NSServiceGroup()
    sg.set_servicegroupname(sg_name)
    try:
        sg = NSServiceGroup.get(nitro, sg)
    except NSNitroError as error:
        log.debug('netscaler module error - NSServiceGroup.get() failed: %s', error)
        sg = None
    _disconnect(nitro)
    return sg