new_contents: from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy import create_engine
  
  engine = create_engine('postgresql://wn:wn@localhost:5432/wndb')
  
  Base = declarative_base()
  
  from sqlalchemy import Column, Integer, Float, DateTime, Boolean, String
  class Observation(Base):
      __tablename__ = 'obs'
  
      id = Column(Integer, primary_key=True)
      station_name = Column(String)
      x = Column(Float)
      y = Column(Float)
      z = Column(Float)
      jam_indicator = Column(Boolean)
      jam_intensity = Column(Float)
      date_time = Column(DateTime)
  
      def __repr__(self):
         return "<Observation(station_name='%r', x='%f', y='%f', z='%f', jam_indicator='%r', jam_intensity='%f', date_time='%r')>" % (
                              self.station_name, self.x, self.y, self.z, self.jam_indicator, self.jam_intensity, self.date_time)
  
  Base.metadata.create_all(engine)
  
  
subject: Update data model.