Demonstrates hybrid properties, which offer the ability to provide equivalent functionality at the instance and query levels with the same attribute name, reducing complexity therefore cognitive load

hybrid-attr.py

class Assignment(Model):
    completed_at = Column(DateTime)
    
    @hybrid_property
    def completed(self):
        return self.completed_at is not None
    
    # Note this is a class method
    @completed.expression
    def completed(cls):
        # The != instead of "is not" demonstrates we're no longer reasoning
        # about Python objects, but SQL stuffs
        return cls.completed_at != None


assignment = Assignment.query.filter(Assignment.completed).first()
assert assignment.completed

# Do *that* shit with Django!