code: def _generate_base_namespace_module(self, namespace):
          # type: (ApiNamespace) -> None
          
  
          self.cur_namespace = namespace
          self.import_tracker.clear()
          generate_module_header(self)
  
          self.emit_placeholder('imports_needed_for_typing')
          self.emit_raw(validators_import_with_type_ignore)
  
          # Generate import statements for all referenced namespaces.
          self._generate_imports_for_referenced_namespaces(namespace)
  
          self._generate_typevars()
  
          for annotation_type in namespace.annotation_types:
              self._generate_annotation_type_class(namespace, annotation_type)
  
          for data_type in namespace.linearize_data_types():
              if isinstance(data_type, Struct):
                  self._generate_struct_class(namespace, data_type)
              elif isinstance(data_type, Union):
                  self._generate_union_class(namespace, data_type)
              else:
                  raise TypeError('Cannot handle type %r' % type(data_type))
  
          for alias in namespace.linearize_aliases():
              self._generate_alias_definition(namespace, alias)
  
          self._generate_routes(namespace)
          self._generate_imports_needed_for_typing()
docs: Creates a module for the namespace. All data types and routes are
          represented as Python classes.