Django PickleField CRUD Mixin

PickleFieldMixin.py

class PickleFieldMixin(object):
    """Django PickleField CRUD Mixin.
    Replace 'field' with PickleField field. 
    Replace 'model' with appropriate model containing \
    this mixin. 
    """

    def attr_create(self, key, value=None):
        key = str(key)

        try:
            if self.field.get(key, None):
                raise Exception
        except:
            print('Attempt to create key, which already exists.')
        else:
            self.field[key] = value
            self.save()

            return True
    
    def attr_read(self, key):
        key = str(key)

        try:
            self.field[key]
        except KeyError:
            print('Key does not exist.')
        else:
            return self.field[key]

    def attr_update(self, key, value):
        key = str(key)

        try:
            self.field[key]
        except KeyError:
            print('Key does not exist.')
        else:
            self.field[key] = value
            self.save()

            return self.field[key]

    def attr_delete(self, key):
        key = str(key)

        try:
            self.field[key]
        except KeyError:
            print('Key does not exist.')
        else:
            self.field[key] = None
            self.save()

            return self.field[key]

    def init_field(self):
        if not self.field:
            field = {}
    
    def save(self, *args, **kwargs):
        self.init_field()
        
        return super(model, self).save(*args, **kwargs)