diff --git a/src/my_package/data.py b/src/my_package/data.py
index 23889d1..55fda66 100644
--- a/src/my_package/data.py
+++ b/src/my_package/data.py
@@ -4,12 +4,18 @@
 from dotenv import load_dotenv
 import json
 import pandas as pd
+import sys
 
 load_dotenv()
 
-# Gets the key, from my env file
+# Gets the key, from the .env file
 API_KEY = os.getenv("API_KEY")
 
+# Check if API_KET exsist in the .env file
+if API_KEY is None:
+    print("Error! Missing the environment variable: `API_KEY`. Check `resources/README.md` for setup configurations.")
+    raise EnvironmentError("Missing API_KEY") # Raise error
+
 # Gets the current data from the API - openweathermap.org
 def fetch_current_data(city_name):
    
diff --git a/tests/unit/test_format_yeardata.py b/tests/unit/test_format_yeardata.py
index ee73a61..7c5363b 100644
--- a/tests/unit/test_format_yeardata.py
+++ b/tests/unit/test_format_yeardata.py
@@ -72,11 +72,17 @@ def test_fetch_data_failure(self, mock_get):
     
     def test_api_key_in_env(self):
         # Check if the API_KEY is loaded from the environment
-        api_key = os.getenv("API_KEY")
+        API_KEY = os.getenv("API_KEY")
+
+
+        # Check if API_KET exsist in the .env file
+        if API_KEY is None:
+            print("Error! Missing the environment variable: `API_KEY`. Check `resources/README.md` for setup configurations.")
+            raise EnvironmentError("Missing API_KEY") # Raise error
         
-        self.assertIsNotNone(api_key, "API_KEY is not set in the environment.")
-        self.assertIsInstance(api_key, str)
-        self.assertGreater(len(api_key), 0, "API_KEY should not be an empty string.")
+        self.assertIsNotNone(API_KEY, "API_KEY is not set in the environment.")
+        self.assertIsInstance(API_KEY, str)
+        self.assertGreater(len(API_KEY), 0, "API_KEY should not be an empty string.")
 
 if __name__ == '__main__':
     unittest.main()