code: def visit_Module(self, node):
          
          self.generic_visit(node)
          import_alias = ast.alias(name='itertools', asname=mangle('itertools'))
          if self.use_itertools:
              importIt = ast.Import(names=[import_alias])
              node.body.insert(0, importIt)
          return node
docs: Add itertools import for imap, izip or ifilter iterator.