如何将'using‘DB传递给django connection对象

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'default_db',
        'USER': 'db_user',
        'PASSWORD': 'db_password',
        'HOST': 'localhost',
        'PORT': '3306',
    },
    'secondary': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'secondary_db',
        'USER': 'db_user',
        'PASSWORD': 'db_password',
        'HOST': 'localhost',
        'PORT': '3306',
    }
}

from django.db import connections

# 使用默认数据库连接
default_connection = connections['default']
default_connection.cursor()

# 使用第二个数据库连接
secondary_connection = connections['secondary']
secondary_connection.cursor()