For https://github.com/jonathanslenders/ptpython/issues/155 . Edit datastructures in yaml using vim.

vim.py

from yaml import load, dump
try:
    from yaml import CLoader as Loader, CDumper as Dumper
except ImportError:
    from yaml import Loader, Dumper
import yaml, tempfile, subprocess, sys

def edit(data):

    fd, temp_path = tempfile.mkstemp(prefix='punctual.')
    with open(temp_path, "r+") as f:
        f.write(yaml.safe_dump(data, default_flow_style=False, allow_unicode=True))
        f.truncate()
        f.close()

    while True:
        with open(temp_path, "r+") as f:
            subprocess.check_call('vim -c "set syntax=yaml" ' + temp_path, shell=True)
            f.close
        try:
          data = yaml.load(open(temp_path,"r+").read())
          break
        except Exception as E:
          print(E)
          input("Press Enter to continue...")
    return data

edit({})

An example of some bad data for you

foo:
 - biz
 - baz
 - buz
 bar:
  - fiz
  - faz
  - fuz

And some good data

Foo:
- biz
- baz
- buz
- Bar:
  - fiz
  - faz
  - fuz