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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 _loadSources(self):
 """creates a trigdict and populates it with data from self.autorityFiles """

        self.confstems = {}
        self.sourceDict = newtrigdict.Trigdict()
        for fName in self.authorityFiles:
            self._loadOneSource(fName)
        # We want to allow naked bibstems in references, too
        for stem in self.sourceDict.values():
            cleanStem = stem.replace(".", "").upper()
            self._addPub(stem, cleanStem)