Testing Singleton

app/coordinates.py

@@ -1,15 +1,19 @@
 """app.coordinates.py"""
+
+
 class Coordinates:
     """
     A position on earth using decimal coordinates (latitude and longitude).
     """
+
     def __init__(self, latitude, longitude):
         self.latitude = latitude
         self.longitude = longitude
 
     def serialize(self):
         """
         Serializes the coordinates into a dict.
+
         :returns: The serialized coordinates.
         :rtype: dict
         """

app/data/__init__.py

@@ -14,6 +14,7 @@
 def data_source(source):
     """
     Retrieves the provided data-source service.
+
     :returns: The service.
     :rtype: LocationService
     """

tests/test_countries.py

@@ -21,3 +21,18 @@
 )
 def test_countries_country_name__country_code(country_name, expected_country_code):
     assert countries.country_code(country_name) == expected_country_code
+
+__shared_instance = None
+@staticmethod
+def getInstance():
+    """Static Access Methods """
+    if Country.__shared_instance == None:
+        Country()
+    return Country.__shared_instance
+
+def __init__(self) -> None:
+    """ Virtual Private Constructor"""
+    if Country.__shared_instance != None:
+        raise Exception("Singleton Class already initialized. Please use getInstance()")
+    else:
+        Country.__shared_instance = self