from sqlalchemy import Column, Integer, ForeignKey from platypush.common.db import Base from .sensors import NumericSensor if 'weight_sensor' not in Base.metadata: class WeightSensor(NumericSensor): """ A sensor that measures weight. """ __tablename__ = 'weight_sensor' id = Column( Integer, ForeignKey(NumericSensor.id, ondelete='CASCADE'), primary_key=True ) __mapper_args__ = { 'polymorphic_identity': __tablename__, }