* failing unit test for issue 3962
* attempt to fix Issue #3962
* create artificial unit test example
* using length instead of self.length
* sp
* reformat with black
* find better ancestor within span and use generic 'dep'
* attach to span.root if there is no appropriate ancestor
* comment span text
* clean up ancestor code
* reconstruct dep tree to keep same number of sentences
Ines Montani