new_contents: """
  Goal: simplify the code when interacting with entities
  """
  import sqlalchemy as db
  
  
  class CRUDMixin():
      """ Helper class sqlalchemy entities """
      __table_args__ = {'extend_existing': True}
  
      id = db.Column(db.Integer, primary_key=True)
  
      @classmethod
      def get_by_id(cls, id):
          if any(
              (isinstance(id, str) and id.isdigit(),
               isinstance(id, (int, float))),):
              return cls.query.get(int(id))
          return None
  
      @classmethod
      def create(cls, **kwargs):
          """ Helper for session.add() + session.commit() """
          instance = cls(**kwargs)
          return instance.save()
  
      def update(self, commit=True, **kwargs):
          for attr, value in kwargs.items():
              setattr(self, attr, value)
          return self.save() if commit else self
  
      def save(self, commit=True):
          db.session.add(self)
          if commit:
              db.session.commit()
          return self
  
      def delete(self, commit=True):
          db.session.delete(self)
          return commit and db.session.commit()
  
subject: Save olass/models/crud_mixin.py needs refactoring in order to have access to the `session`