Hi there,

I have an app that needs repeating in the middle and the end of the experiment, so was trying to create abstract base classes for Player, Group and Subsession, however I get an error. (I'm using otree 5.8.0)
__________________
Models.py:

class SharedBasePlayer(BasePlayer):
    __abstract__ = True
    choice = models.StringField()

class Player(SharedBasePlayer):
    pass
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Error message:
...
  File "/home/s/.local/lib/python3.8/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
    raise exception
AttributeError: Neither 'OTreeColumn' object nor 'Comparator' object has an attribute 'form_props'


Thanks in advance
Scott

Since you mentioned that the objective is to create “an app that needs repeating in the middle and the end of the experiment,” this may be of help: https://groups.google.com/g/otree/c/2Z3d_SStb5o/m/kEjHjBL_BAAJ.