Fix a reST formatting error

pep-0443.txt

@@ -192,16 +192,17 @@ argument which includes the relevant ABCs. The algorithm is as follows::
 
 In its most basic form, it returns the MRO for the given type::
 
->>> _compose_mro(dict, [])
-[<class 'dict'>, <class 'object'>]
+  >>> _compose_mro(dict, [])
+  [<class 'dict'>, <class 'object'>]
 
 When the haystack consists of ABCs that the specified type is a subclass
 of, they are inserted in a predictable order::
 
->>> _compose_mro(dict, [Sized, MutableMapping, str, Sequence, Iterable])
-[<class 'dict'>, <class 'collections.abc.MutableMapping'>,
- <class 'collections.abc.Iterable'>, <class 'collections.abc.Sized'>,
- <class 'object'>]
+  >>> _compose_mro(dict, [Sized, MutableMapping, str,
+  ...                     Sequence, Iterable])
+  [<class 'dict'>, <class 'collections.abc.MutableMapping'>,
+   <class 'collections.abc.Iterable'>, <class 'collections.abc.Sized'>,
+   <class 'object'>]
 
 While this mode of operation is significantly slower, no caching is
 involved because user code may ``register()`` a new class on an ABC at