Oracle pl / sql提供环境特定参数的首选方式

What is the preferred way to provide parameters (configuration) for pl/sql packages? Having different environments (test, qa, prd) there is a need for specifying values which should be set appropriately for each environment. Once the package is installed these values won't change. I'm looking for a way which preferably allows having the same code for every environment.What is the preferred way to provide parameters