So there are two choices in mind: 1. Use the —config option so you can define that in YAML. 2. Use a resolver to do that conversion I find it weird to supply a null value in CLI as an argument. I am less sure if the 2. Option work, maybe there are better ways

As i understand the library you used has a default value, is that align with what you want? Otherwise there is a simple solution, which you use runtime_params resolver, where the default will be None. And you only pass in value if you want it to be something else.

Thank you @Ankita Katiyar for the suggestion below. @Miguel Angel Ortiz Marin you can make use of custom_resolvers as a work-around. settings.py

def my_resolver(key):
    if key == 'None':
        return None

CONFIG_LOADER_ARGS = {
      "base_env": "base",
      "default_run_env": "local",
      "custom_resolvers": {
             "my_resolver": lambda key: my_resolver(key),
      }       }
}

and parameters.yml

my_param: ${my_resolver:${runtime_params:key}}