code: def _post_build(self, module, encoding):
          
          module.file_encoding = encoding
          self._manager.cache_module(module)
          # post tree building steps after we stored the module in the cache:
          for from_node in module._import_from_nodes:
              if from_node.modname == "__future__":
                  for symbol, _ in from_node.names:
                      module.future_imports.add(symbol)
              self.add_from_names_to_locals(from_node)
          # handle delayed assattr nodes
          for delayed in module._delayed_assattr:
              self.delayed_assattr(delayed)
  
          # Visit the transforms
          if self._apply_transforms:
              module = self._manager.visit_transforms(module)
          return module
docs: Handles encoding and delayed nodes after a module has been built