Issue #23921: Standardized documentation whitespace formatting.
Original patch by James Edwards.
diff --git a/Doc/tutorial/classes.rst b/Doc/tutorial/classes.rst
index d82adf6..b1f3f00 100644
--- a/Doc/tutorial/classes.rst
+++ b/Doc/tutorial/classes.rst
@@ -210,6 +210,7 @@
    class MyClass:
        """A simple example class"""
        i = 12345
+
        def f(self):
            return 'hello world'
 
@@ -458,8 +459,10 @@
 
    class C:
        f = f1
+
        def g(self):
            return 'hello world'
+
        h = g
 
 Now ``f``, ``g`` and ``h`` are all attributes of class :class:`C` that refer to
@@ -473,8 +476,10 @@
    class Bag:
        def __init__(self):
            self.data = []
+
        def add(self, x):
            self.data.append(x)
+
        def addtwice(self, x):
            self.add(x)
            self.add(x)
@@ -670,7 +675,7 @@
    class Employee:
        pass
 
-   john = Employee() # Create an empty employee record
+   john = Employee()  # Create an empty employee record
 
    # Fill the fields of the record
    john.name = 'John Doe'
@@ -796,8 +801,10 @@
        def __init__(self, data):
            self.data = data
            self.index = len(data)
+
        def __iter__(self):
            return self
+
        def next(self):
            if self.index == 0:
                raise StopIteration