old_contents: from sqlalchemy import Column, Integer, String, Boolean
  from sqlalchemy.sql.schema import ForeignKey
  from sqlalchemy.orm import relationship
  
  from sqlalchemy.ext.declarative import declarative_base
  
  Base = declarative_base()
  
  class Developer(Base):
      __tablename__ = 'developer'
  
      id = Column(Integer, primary_key=True)
      name = Column(String(50), nullable=False)
      last_name = Column(String(50), nullable=False)
      mail = Column(String(100), nullable=False)
      enabled = Column(Boolean, nullable=False, default=True)
  
      projects = relationship('Project')
  
  
  class ProjectDeveloper(Base):
      __tablename__ = 'project_developer'
  
      dev_id = Column(Integer, ForeignKey('developer.id'), primary_key=True)
      pro_id = Column(Integer, ForeignKey('project.id'), primary_key=True)
  
  
  class Project(Base):
      __tablename__ = 'project'
  
      id = Column(Integer, primary_key=True)
      name = Column(String(50), nullable=False)
      enabled = Column(Boolean, nullable=False, default=True)
  
new_contents: import datetime
  from sqlalchemy import Column, Integer, String, Boolean, DateTime
  from sqlalchemy.sql.schema import ForeignKey
  from sqlalchemy.orm import relationship
  
  from sqlalchemy.ext.declarative import declarative_base
  
  Base = declarative_base()
  
  
  class Developer(Base):
      __tablename__ = 'developer'
  
      id = Column(Integer, primary_key=True)
      name = Column(String(50), nullable=False)
      description = Column(String(255), nullable=False)
      meeting_days = Column(Integer, nullable=False)
      enabled = Column(Boolean, nullable=False, default=True)
      timestamp_created = Column(DateTime, nullable=False, default=datetime.datetime.utcnow)
      timestamp_modif = Column(DateTime, nullable=False)
  
      projects = relationship('Project')
  
  
  class ProjectDeveloper(Base):
      __tablename__ = 'project_developer'
  
      fk_proj = Column(Integer, ForeignKey('developer.id'), primary_key=True)
      fk_dev = Column(Integer, ForeignKey('project.id'), primary_key=True)
  
  
  class Project(Base):
      __tablename__ = 'project'
  
      id = Column(Integer, primary_key=True)
      first_name = Column(String(50), nullable=False)
      last_name = Column(String(50), nullable=False)
      phone = Column(String(20), nullable=False)
      experience = Column(String(255), nullable=False)
      skills = Column(String(255), nullable=False)
      mail = Column(String(100), nullable=False)
      password = Column(String(100), nullable=False)
      fk_role = Column(Integer, ForeignKey('role_dev.id'), primary_key=True)
      enabled = Column(Boolean, nullable=False, default=True)
  
  
  class RoleDev(Base):
      __tablename__ = 'role_dev'
      id = Column(Integer, primary_key=True)
      name = Column(String(50), nullable=False)
  
subject: update models