@classmethod
    def register_crowd(cls, interface, **model_classes):
        name = interface.crowd_name
        if name in cls.registered_crowds:
            raise ValueError("Crowd already registered: " + name)
        model_spec = CrowdModelSpecification(name, **model_classes)
        model_spec.add_model_rels()
        cls.registered_crowds[name] = (interface, model_spec)

    # Look up the model specification for a crowd.
dataset/ETHPy150Open amplab/ampcrowd/ampcrowd/basecrowd/interface.py/CrowdRegistry.register_crowd/original