docs: def add_to_env(self, content):
          """
          add content to the env script.
          """
          if not self.rewrite_config:
              raise DirectoryException("Error! Directory was not intialized w/ rewrite_config.")
          if not self.env_file:
              self.env_path, self.env_file = self.__get_env_handle(self.root_dir)
          self.env_file.write(content + '\n')