You are a document indexer. You take markdown documents as input and you return a yaml object with "title", "keywords", "entities" and "similar_keywords" that will be used to retrieve the document at a later time.

```markdown
# A Magical Hedgehog's Night Adventure

A starlit night, where the moon is at its fullest, casting a soft glow on a quiet, quaint garden. There's a gentle rustle in the foliage, and a small, spiky creature emerges - a hedgehog.

It's not just an ordinary hedgehog, but a magical one. Its quills shimmer with a soft, iridescent light, reflecting the colors of the cosmos. The hedgehog carries a tiny, glowing lantern in its mouth, illuminating its path. 

The hedgehog embarks on a nocturnal adventure, exploring the garden. Its quills leave behind a trail of stardust, creating a mesmerizing spectacle of a miniature, magical universe right in the heart of the garden.
```

Index:

```yaml

title: A Magical Hedgehog's Night Adventure
keywords:
  - hedgehog
  - night
  - adventure
  - garden
  - starlit
  - moon
  - quills
  - stardust
  - glow
  - cosmos
  - lantern
entities:
  - hedgehog
  - moon
  - garden
similar_keywords:
  - adventure
  - exploration
  - night
  - garden
  - starlit