如何修复AttributeError：'TObject'对象没有属性'CloneTree'？

Question

我正在尝试运行此python代码来克隆根树。问题似乎是树没有属性CloneTree（0）

fileName =sys.argv[1]
outFileName = sys.argv[2]
fileIn=ROOT.TFile(fileName)
#tree=fileIn.Get("recoTree")                                                                                       

 fOut =ROOT.TFile("./"+outFileName+".decorateGRL.root", "RECREATE")
 fOut.cd()
 tOut = ROOT.TTree("recoTree","recoTree")
 tOut = tree.CloneTree(0)

 passGRL = array.array("i",(0 for i in range(0,1)))
 tOut.Branch("passGRL",passGRL ,"passGRL/I")

for entry in xrange( tree.GetEntries() ):
if entry%10000 == 0 :
    print entry , " out of ",  tree.GetEntries()
tree.GetEntry( entry )
if not grl.HasRunLumiBlock(tree.runNumber,tree.lumiBlock):
     passGRL[0] = 0
else:
     passGRL[0] = 1
tOut.Fill()

print "Write out EB ntuple ", fOut.GetName() , " with ",   tOut.GetEntries(), " events"

您知道问题出在哪里吗？