some exception handling and hints what fails would be nice

[ksuess]

a simple print(option) helps to see what fails.

A simple exception handling of parsing would decrease frustration. For example here no comments are allowed and break the build run: mr.developer-2.0.1-py3.8.egg/mr/developer/extension.py", line 107, in get_sources
key, value = option.split('=', 1)

[sources]
collective.fancyaddon = git git@github.com:/ksuess/collective.fancyaddon.git # forked!

do not comment here!

An internal error occurred due to a bug in either zc.buildout or in a
recipe being used:
Traceback (most recent call last):
  File "/Users/batman/schnupsi/work/zope/lib/python3.8/site-packages/zc/buildout/buildout.py", line 2174, in main
    getattr(buildout, command)(args)
  File "/Users/batman/schnupsi/work/zope/lib/python3.8/site-packages/zc/buildout/buildout.py", line 658, in install
    self._load_extensions()
  File "/Users/batman/schnupsi/work/zope/lib/python3.8/site-packages/zc/buildout/buildout.py", line 1194, in _load_extensions
    ep.load()(self)
  File "/Users/batman/schnupsi/work/eggs/mr.developer-2.0.1-py3.8.egg/mr/developer/extension.py", line 296, in extension
    return Extension(buildout)()
  File "/Users/batman/schnupsi/work/eggs/mr.developer-2.0.1-py3.8.egg/mr/developer/extension.py", line 255, in __call__
    auto_checkout = self.get_auto_checkout()
  File "/Users/batman/schnupsi/work/eggs/mr.developer-2.0.1-py3.8.egg/mr/developer/common.py", line 98, in g
    value = f(*args, **kwargs)
  File "/Users/batman/schnupsi/work/eggs/mr.developer-2.0.1-py3.8.egg/mr/developer/extension.py", line 149, in get_auto_checkout
    packages = set(self.get_sources().keys())
  File "/Users/batman/schnupsi/work/eggs/mr.developer-2.0.1-py3.8.egg/mr/developer/common.py", line 98, in g
    value = f(*args, **kwargs)
  File "/Users/batman/schnupsi/work/eggs/mr.developer-2.0.1-py3.8.egg/mr/developer/extension.py", line 107, in get_sources
    key, value = option.split('=', 1)
ValueError: not enough values to unpack (expected 2, got 1)