Improve memory management on the Python side

Improve memory management on the Python side to rely less on the
heuristic memory policy.

Author: guitargeek

python/ShapeTools.py

@@ -909,6 +909,7 @@ def getPdf(self, channel, process, _cache=None):
             stderr.write("Warning: the shapeN implementation in RooStats and L&S are different\n")
         pdfs = ROOT.RooArgList(nominalPdf) if self.options.useHistPdf == "always" else ROOT.TList()
         if self.options.useHistPdf != "always":
+            ROOT.SetOwnership(nominalPdf, False)
             pdfs.Add(nominalPdf)
         coeffs = ROOT.RooArgList()
         minscale = 1
@@ -917,6 +918,8 @@ def getPdf(self, channel, process, _cache=None):
                 pdfs.add(pdfUp)
                 pdfs.add(pdfDown)
             else:
+                ROOT.SetOwnership(pdfUp, False)
+                ROOT.SetOwnership(pdfDown, False)
                 pdfs.Add(pdfUp)
                 pdfs.Add(pdfDown)
             if scale == 1:
@@ -949,6 +952,7 @@ def getPdf(self, channel, process, _cache=None):
                 maxbins = 0
                 for i in range(pdfs.GetSize()):
                     rebinned = self.rebinH1(pdfs.At(i))
+                    ROOT.SetOwnership(rebinned, False)
                     rebins.Add(rebinned)
                     maxbins = max(maxbins, rebinned._original_bins)
                 if channelBinParFlag:
@@ -1264,6 +1268,7 @@ def shape2Pdf(self, shape, channel, process, _cache=None):
                 if self.options.useHistPdf == "never":
                     shape = self.rebinH1(shape)
                     tlist = ROOT.TList()
+                    ROOT.SetOwnership(shape, False)
                     tlist.Add(shape)
                     if channelBinParFlag:
                         rhp = ROOT.CMSHistFunc(