Add support to kml with recursive Document (Sourcery refactored)

[sourcery-ai]

Pull Request #80 refactored by Sourcery.

Since the original Pull Request was opened as a fork in a contributor's
repository, we are unable to create a Pull Request branching from it.

To incorporate these changes, you can either:

1. Merge this Pull Request instead of the original, or

2. Ask your contributor to locally incorporate these commits and push them to
   the original Pull Request

   Incorporate changes via command line

   git fetch https://github.com/cleder/fastkml pull/80/head
   git merge --ff-only FETCH_HEAD
   git push

NOTE: As code is pushed to the original Pull Request, Sourcery will
re-run and update (force-push) this Pull Request with new refactorings as
necessary. If Sourcery finds no refactorings at any point, this Pull Request
will be closed automatically.

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[sourcery-ai]

Sourcery Code Quality Report

❌  Merging this PR will decrease code quality in the affected files by 0.06%.

Quality metrics	Before	After	Change
Complexity	6.56 ⭐	6.48 ⭐	-0.08 👍
Method Length	48.25 ⭐	48.53 ⭐	0.28 👎
Working memory	6.65 🙂	6.64 🙂	-0.01 👍
Quality	72.14% 🙂	72.08% 🙂	-0.06% 👎

Other metrics	Before	After	Change
Lines	1076	1074	-2

Changed files	Quality Before	Quality After	Quality Change
fastkml/kml.py	72.14% 🙂	72.08% 🙂	-0.06% 👎

Here are some functions in these files that still need a tune-up:

File	Function	Complexity	Length	Working Memory	Quality	Recommendation
fastkml/kml.py	_Feature.from_element	21 😞	395 ⛔	8 🙂	36.79% 😞	Refactor to reduce nesting. Try splitting into smaller methods
fastkml/kml.py	_Feature.etree_element	21 😞	287 ⛔	7 🙂	41.68% 😞	Refactor to reduce nesting. Try splitting into smaller methods
fastkml/kml.py	Placemark.from_element	7 ⭐	241 ⛔	10 😞	48.86% 😞	Try splitting into smaller methods. Extract out complex expressions
fastkml/kml.py	_TimePrimitive.parse_str	6 ⭐	146 😞	12 😞	53.78% 🙂	Try splitting into smaller methods. Extract out complex expressions
fastkml/kml.py	GroundOverlay.from_element	13 🙂	152 😞	6 ⭐	59.42% 🙂	Try splitting into smaller methods

Legend and Explanation

The emojis denote the absolute quality of the code:

• ⭐ excellent
• 🙂 good
• 😞 poor
• ⛔ very poor

The 👍 and 👎 indicate whether the quality has improved or gotten worse with this pull request.

---

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[cleder]

Quality gate: Passed

Everything looks good
Details