old_contents: from sqlalchemy import Column, Integer, String, ForeignKey, Boolean
  from sqlalchemy.orm import relationship
  
  from .. import db
  
  
  class UUID(db.Model):
  
      __tablename__ = 'uuid'
  
      id = Column(Integer, primary_key=True)
      user_identifier = Column(String(100), unique=True)
      crashreport_black_listed = Column(Boolean(False), default=False)
      usagestats_black_listed = Column(Boolean(False), default=False)
      alias = relationship('Alias', back_populates='uuid', uselist=False)
      group_id = Column(Integer, ForeignKey('group.id'))
      group = relationship('Group', uselist=True, foreign_keys=[group_id])
  
      def __init__(self, user_identifier):
          self.user_identifier = user_identifier
  
      def __repr__(self):
          return "%d. %s" % (self.id, self.user_identifier)
  
new_contents: from sqlalchemy import Column, Integer, String, ForeignKey, Boolean
  from sqlalchemy.orm import relationship
  
  from .. import db
  
  
  class UUID(db.Model):
  
      __tablename__ = 'uuid'
  
      id = Column(Integer, primary_key=True)
      user_identifier = Column(String(100), unique=True)
      crashreport_black_listed = Column(Boolean(False), default=False)
      usagestats_black_listed = Column(Boolean(False), default=False)
      alias = relationship('Alias', back_populates='uuid', uselist=True)
      group_id = Column(Integer, ForeignKey('group.id'))
      group = relationship('Group', uselist=True, foreign_keys=[group_id])
  
      def __init__(self, user_identifier):
          self.user_identifier = user_identifier
  
      def __repr__(self):
          return "%d. %s" % (self.id, self.user_identifier)
  
subject: allow multiple aliases in UUID model (one to many)