The method 1, wherein ascertaining whether the fault exists comprises determining {TAIL ~ a type} of {HEAD ~ the fault} 
The method 1 , wherein ascertaining whether the fault exists comprises determining { TAIL ~ a type } of { HEAD ~ the fault }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD