prompt: Your task is to convert an English description into an ASCII tree format using this style:
  ```
  custom_resolve_dir
   +--testproj
   |   `--__snapshots__
   `--testproj2
       `--__snapshots__
  ```
  
  Convert this description:
  
  nested-n_m is a root directory that features 2 subdirectories: a and node_modules.
  At the top level, 'a' retains 1 contained folders: b.
  At level 2, in directory path 'a / b', 'b' keeps 1 subfolders: c.
  Within directory hierarchy 'a / b / c', 'c' includes 1 subdirectories: d.
  Within directory hierarchy 'a → b → c → d', The 'd' data structure appears to be unused.
  At the main level, 'node_modules' has been left empty.
  
  
  Provide your answer wrapped in <ascii_formatted> tags.
verification_info: {"ground_truth": "nested-n_m\n +--a\n |   `--b\n |       `--c\n |           `--d\n `--node_modules", "description": "nested-n_m is a root directory that features 2 subdirectories: a and node_modules.\nAt the top level, 'a' retains 1 contained folders: b.\nAt level 2, in directory path 'a / b', 'b' keeps 1 subfolders: c.\nWithin directory hierarchy 'a / b / c', 'c' includes 1 subdirectories: d.\nWithin directory hierarchy 'a \u2192 b \u2192 c \u2192 d', The 'd' data structure appears to be unused.\nAt the main level, 'node_modules' has been left empty.\n"}