import os

import argparse

def get_env_var(var_name, default=None):

"""Retrieves an environment variable, returning a default if it's not set."""

try:

return os.environ[var_name]

except KeyError:

return default

def main():

parser = argparse.ArgumentParser(description="A quick prototype using environment variables.")

parser.add_argument("--name", type=str, help="The name to greet.")

parser.add_argument("--debug", action="store_true", help="Enable debug mode.")

args = parser.parse_args()

# Get environment variables with defaults

api_key = get_env_var("API_KEY", "default_api_key")

log_level = get_env_var("LOG_LEVEL", "INFO")

data_url = get_env_var("DATA_URL", "http://example.com/data")

# Use the environment variables

print(f"API Key: {api_key}")

print(f"Log Level: {log_level}")

print(f"Data URL: {data_url}")

if args.name:

print(f"Hello, {args.name}!")

if args.debug:

print("Debug mode enabled.")

if __name__ == "__main__":

main()