AttributeError: type object 'Temporal' has no attribute 'activity_class'

[kootenpv]

I tried both purely the example from the docs, and this example which I would imagine should just work.

Any idea what could be wrong?

import sqlalchemy as sa
import sqlalchemy.orm as orm
import temporal_sqlalchemy as temporal
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base

sessionmaker = orm.sessionmaker()
session = sessionmaker()
temporal.temporal_session(session)

# postgres 11 from docker
connection_string = "postgresql://postgres:mysecretpassword@127.0.0.1:5432/test"
engine = create_engine(connection_string, echo=True)

Base = declarative_base()

class MyModel(Base, temporal.TemporalModel):
    __tablename__ = 'my_model_table'
    __table_args__ = {'schema': 'my_schema'}

    id = sa.Column(sa.BigInteger, primary_key=True)
    description = sa.Column(sa.Text)

    class Temporal:
        track = ('description', )

# It crashes here with
# AttributeError: type object 'Temporal' has no attribute 'activity_class'

Base.metadata.create_all(engine)

m = MyModel()
session.add(m)
session.commit()