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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 sort_versions(self):
 """Sort entries by version. The order is typically descending, but package order functions can change this. """

        if self.sorted:
            return

        for orderer in (self.solver.package_orderers or []):
            entries = orderer.reorder(self.entries, key=lambda x: x.package)
            if entries is not None:
                self.entries = entries
                self.sorted = True

                if self.pr:
                    self.pr("sorted: %s packages: %s", self.package_name, repr(orderer))
                return

        # default ordering is version descending
        self.entries = sorted(self.entries, key=lambda x: x.version, reverse=True)
        self.sorted = True

        if self.pr:
            self.pr("sorted: %s packages: version descending", self.package_name)