Python: Choosing between multiple config files based on the number of arguments passed

I am very new to python and have a project in which I am working on the following:

I have 2 py config files with multiple parameters inside them. They named config_default and config_custom both with the function name def config().

Config default has predefined parameters and for config_custom.py, the parameters are passed from the command line arguments.

Problem:

To choose between these two files when the main script with variable number of arguments is executed.

1. If the argument has length = 1, then choose config_default and all the other python scripts in the project uses parameters from config() of config_default whenever imported.
2. If it has more arguments, corresponding values must be assigned to parameters in the function config() of config_custom.

What I tried:

I tried using *args and checked the length of arguments and assigned file path to variable named config. Then trying to import it in all the scripts, but it doesn't work.

Here is the snippet.

def main(*args):
args = sys.argv[1:]
if (len(sys.argv) == 1):
    project_name = sys.argv[0]
    config_file = "./config_default.py"
elif (len(sys.argv) == 3):
    project_name = sys.argv[0]
    process = sys.argv[1]
    spice_version = sys.argv[2]
    config_file = "./config_custom.py"
else:
    print("Error: Check the arguments")
    sys.exit()

Then using "import config" to import.

The error is: ModuleNotFoundError: No module named 'config'