def write(self, output_io):
        '''Write a taxonomy to an open stream out in GG format. Code calling this
        function must open and close the io object.'''
        for name, tax in self.taxonomy.items():
            output_io.write("%s\t%s\n" % (name, '; '.join(tax)))
Write a taxonomy to an open stream out in GG format. Code calling this
        function must open and close the io object.