Python peewee:在连接之前，如何在一列上选择不同的值？

from peewee import *

# 创建数据库连接
db = SqliteDatabase('my_database.db')

# 定义模型类
class MyModel(Model):
    column = CharField()

    class Meta:
        database = db

# 创建表格
db.create_tables([MyModel])

# 插入数据
MyModel.create(column='value1')
MyModel.create(column='value2')
MyModel.create(column='value3')

# 查询数据并选择不同的值
query = (MyModel
         .select(MyModel.column,
                 Case(None, [(MyModel.column == 'value1', 'A'),
                             (MyModel.column == 'value2', 'B'),
                             (MyModel.column == 'value3', 'C')],
                      'D')
                 .alias('new_column'))
         .order_by(MyModel.column))

# 执行查询
results = query.execute()

# 输出结果
for row in results:
    print(row.new_column)