genotype_to_string and genotype_to_text failure about gnomic HOT 5 CLOSED

from gnomic.utils import genotype_to_string, genotype_to_text, change_to_text, change_to_string

from gnomic import Mutation, FeatureTree, Feature, Accession

g = Mutation(new=FeatureTree(Feature(type='reaction', accession=Accession(identifier='3OAR140'), variant='down-regulation(-0.996)')), old=FeatureTree(Feature(type='reaction', accession=Accession(identifier='3OAR140'))), multiple=False)
change_to_string(g)

AttributeError                            Traceback (most recent call last)
<ipython-input-43-561e8086745e> in <module>()
      4 
      5 g = Mutation(new=FeatureTree(Feature(type='reaction', accession=Accession(identifier='3OAR140'), variant='down-regulation(-0.996)')), old=FeatureTree(Feature(type='reaction', accession=Accession(identifier='3OAR140'))), multiple=False)
----> 6 change_to_string(g)

/Users/niso/anaconda3/lib/python3.5/site-packages/gnomic/utils.py in change_to_string(change)
    118                 s = '{}>>{}'.format(feature_to_string(change.old), feature_to_string(change.new))
    119             else:
--> 120                 s = '{}>{}'.format(feature_to_string(change.old), feature_to_string(change.new))
    121         elif change.old is None:
    122             # FIXME phenotypes should not have a + or - prefix; only a postfix.

/Users/niso/anaconda3/lib/python3.5/site-packages/gnomic/utils.py in feature_to_string(feature)
    146         return ':'.join(feature_to_string(f) for f in feature.contents)
    147     elif isinstance(feature, FeatureTree):
--> 148         contents = ' '.join(feature_to_string(f) for f in feature.contents)
    149         if isinstance(feature, FeatureSet):
    150             return '{{{contents}}}'.format(contents=contents)

/Users/niso/anaconda3/lib/python3.5/site-packages/gnomic/utils.py in <genexpr>(.0)
    146         return ':'.join(feature_to_string(f) for f in feature.contents)
    147     elif isinstance(feature, FeatureTree):
--> 148         contents = ' '.join(feature_to_string(f) for f in feature.contents)
    149         if isinstance(feature, FeatureSet):
    150             return '{{{contents}}}'.format(contents=contents)

/Users/niso/anaconda3/lib/python3.5/site-packages/gnomic/utils.py in feature_to_string(feature)
    146         return ':'.join(feature_to_string(f) for f in feature.contents)
    147     elif isinstance(feature, FeatureTree):
--> 148         contents = ' '.join(feature_to_string(f) for f in feature.contents)
    149         if isinstance(feature, FeatureSet):
    150             return '{{{contents}}}'.format(contents=contents)

/Users/niso/anaconda3/lib/python3.5/site-packages/gnomic/utils.py in <genexpr>(.0)
    146         return ':'.join(feature_to_string(f) for f in feature.contents)
    147     elif isinstance(feature, FeatureTree):
--> 148         contents = ' '.join(feature_to_string(f) for f in feature.contents)
    149         if isinstance(feature, FeatureSet):
    150             return '{{{contents}}}'.format(contents=contents)

/Users/niso/anaconda3/lib/python3.5/site-packages/gnomic/utils.py in feature_to_string(feature)
    155     else:
    156         s = ''
--> 157         if feature.type and feature.type.name != 'phene':
    158             s += '{}.'.format(feature.type.name)
    159 

AttributeError: 'str' object has no attribute 'name'