Fix README example

Author: eddiezane

README.rst

@@ -72,9 +72,10 @@ Usage
 To begin using this library create a new instance of `SendGridClient` with your SendGrid credentials or a SendGrid API Key. API Key is the preferred method. API Keys are in beta. To configure API keys, visit https://sendgrid.com/beta/settings/api_key.
 
 .. code:: python
-  sg = sendgrid.SendGridClient('sendgrid_username', 'sendgrid_password')
-  # or
-  sg = sendgrid.SendGridClient('sendgrid_apikey')
+
+    sg = sendgrid.SendGridClient('sendgrid_username', 'sendgrid_password')
+    # or
+    sg = sendgrid.SendGridClient('sendgrid_apikey')
 
 Methods
 ~~~~~~~