typing: API_KEY is a str

Author: cclauss

Diff for: web_programming/currency_converter.py

@@ -9,7 +9,7 @@
 
 URL_BASE = "https://www.amdoren.com/api/currency.php"
 TESTING = os.getenv("CI", False)
-API_KEY = os.getenv("AMDOREN_API_KEY")
+API_KEY = os.getenv("AMDOREN_API_KEY", "")
 if not API_KEY and not TESTING:
     raise KeyError("Please put your API key in an environment variable.")