Update what is DI page

docs/introduction/what_is_di.rst

@@ -83,14 +83,12 @@ Let's go through the code of ``example.py``:
 
 .. literalinclude:: ../../examples/di_demo/example.py
    :language: python
-   :linenos:
 
-At some point, things defined above mean, that the code from ``example.py``, 
+At some point, things defined above mean, that the code from ``example.py``,
 could look different, like in ``example_di.py``:
 
 .. literalinclude:: ../../examples/di_demo/example_di.py
    :language: python
-   :linenos:
 
 Best explanation, ever
 ~~~~~~~~~~~~~~~~~~~~~~

examples/di_demo/example.py

@@ -2,16 +2,16 @@
 
 
 class Service:
-    """Some "Service"."""
+    """The Service."""
 
 
 class Client:
-    """Some "Client" that uses "Service"."""
+    """The Client that uses the Service."""
 
     def __init__(self):
-        """Initialize instance."""
+        """Initialize the Client."""
-        self.service = Service()  # Service instance is created inside Client
+        self.service = Service()  # The Service is created by the Client
 
 
 if __name__ == '__main__':
-    client = Client()  # Application creates Client's instance
+    client = Client()  # Application creates the Client

examples/di_demo/example_di.py

@@ -1,18 +1,18 @@
-"""The Code, that demonstrates dependency injection pattern."""
+"""The Code that demonstrates dependency injection pattern."""
 
 
 class Service:
-    """Some "Service"."""
+    """The Service."""
 
 
 class Client:
-    """Some "Client" that uses "Service"."""
+    """The Client that uses the Service."""
 
-    def __init__(self, service):  # Service instance is injected into Client
+    def __init__(self, service):  # The Service is injected into the Client
-        """Initialize instance."""
+        """Initialize the Client."""
         self.service = service
 
 
 if __name__ == '__main__':
-    service = Service()       # Application creates Service instance
+    service = Service()       # Application creates the Service
-    client = Client(service)  # and inject Service instance into the Client
+    client = Client(service)  # and inject the Service into the Client