test_run_hello_world test fails on Python 3.9 about recast-atlas HOT 2 CLOSED

$ python -c 'from yadage.steering_api import run_workflow'  # no output as import works

$ python -c 'from yadage.steering_api import run_workflow'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/yadage/steering_api.py", line 8, in <module>
    from .steering_object import YadageSteering
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/yadage/steering_object.py", line 5, in <module>
    import adage
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/adage/__init__.py", line 6, in <module>
    from adage.adageobject import adageobject
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/adage/adageobject.py", line 1, in <module>
    import adage.graph
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/adage/graph.py", line 1, in <module>
    import networkx as nx
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/networkx/__init__.py", line 84, in <module>
    import networkx.generators
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/networkx/generators/__init__.py", line 5, in <module>
    from networkx.generators.classic import *
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/networkx/generators/classic.py", line 21, in <module>
    from networkx.algorithms.bipartite.generators import complete_bipartite_graph
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/networkx/algorithms/__init__.py", line 12, in <module>
    from networkx.algorithms.dag import *
  File "/home/feickert/.pyenv/versions/recast-atlas-39/lib/python3.9/site-packages/networkx/algorithms/dag.py", line 2, in <module>
    from fractions import gcd
ImportError: cannot import name 'gcd' from 'fractions' (/home/feickert/.pyenv/versions/3.9.6/lib/python3.9/fractions.py)