Select the latest versioned package in the given range.

        If there are no packages in the range, the selection is cleared.

def select_version(self, version_range):
        """Select the latest versioned package in the given range.

        If there are no packages in the range, the selection is cleared.
        """
        row = -1
        version = None
        for i, package in self.packages.iteritems():
            if package.version in version_range \
                    and (version is None or version < package.version):
                version = package.version
                row = i

        self.clearSelection()
        if row != -1:
            self.selectRow(row)
        return version