Few more updates to Type section of advanced tutorial

doc/tutorials/advanced/ex1/type.txt

@@ -230,6 +230,7 @@ compare equal:
 
  #. Define ``Double.__eq__`` so that all instances of type Double
     are equal. For example:
+
     .. code-block:: python
 
         def __eq__(self, other):
@@ -265,14 +266,14 @@ attempt to clear up the confusion:
   b;``, ``a``, ``b`` and ``c`` would all be Result instances.
 
 * A **subclass of Type** represents a set of Type instances that share
-  structural similarities. In the ``double`` example that we are
-  doing, there is actually only one Type in that set, therefore the
-  subclass doesn't represent anything that one of its instances
-  doesn't. In this case it is a singleton. However, the NDArrayType
-  class which is a subclass of Type represents a set of types of
-  tensors parametrized by their data type or number of dimensions. We
-  could say that subclassing Type builds a hierarchy of Types which is
-  based upon structural similarity rather than compatibility.
+  structural similarities. In the ``double`` example that we are doing,
+  there is actually only one Type in that set, therefore the subclass
+  doesn't represent anything that one of its instances doesn't. In this
+  case it is a singleton, a set with one element. However, the NDArrayType
+  class which is a subclass of Type represents a set of types of tensors
+  parametrized by their data type or number of dimensions. We could say
+  that subclassing Type builds a hierarchy of Types which is based upon
+  structural similarity rather than compatibility.
 
 
 Final version