loadJSON does not define required_keys

[ckikawa]

Hi all, thanks for this very tidy tree drawing package!

In the newest version (v0.3.0) the loadJSON function requires a certain list of keys required_keys but never defines this list. The result is a key error that I could only get around by pinning an earlier version in my environment (v.0.2.2).

Assertion statement with required_keys here:

baltic/baltic/baltic.py

Line 2183 in 5ddbc5f

assert 'name' in json_translation and any(key in json_translation for key in required_keys),'JSON translation dictionary missing entries: %s'%(', '.join([entry for entry in ['name']+length_keys if (entry in json_translation)==False]))

[AAMCgenomics]

Hi @ckikawa I overcome this problem using the source code and adding it as a list with the following values:
required_keys = ['absoluteTime', 'length', 'height']
The source code could be imported in this way:
bt = imp.load_source('baltic', '/path_to_your_library/balticv.py')