Change README.md example to use 'Undefined'.

README.md

@@ -12,20 +12,21 @@ This data can e.g. be used for static analysis, type checking or type inference.
 Each Python module is represented by a `.py` "stub". This is a normal Python
 file (i.e., it can be interpreted by Python 3), except all the methods are empty.
 Python function annotations ([PEP 3107](https://www.python.org/dev/peps/pep-3107/))
-and Python type annotaitons ([PEP 484](http://www.python.org/dev/peps/pep-484/))
 are used to describe the types the function has.
+See ([PEP 484](http://www.python.org/dev/peps/pep-484/)) for the exact syntax
+of the stub files.
 
 ## Example
 
 The below is an excerpt from the types for the `datetime` module.
 
 ```
-MAXYEAR = int()
-MINYEAR = int()
-__doc__ = str()
-__file__ = str()
-__name__ = str()
-__package__ = None
+MAXYEAR = Undefined(int)
+MINYEAR = Undefined(int)
+__doc__ = Undefined(str)
+__file__ = Undefined(str)
+__name__ = Undefined(str)
+__package__ = Undefined(None)
 
 class date(object):
     def __init__(self, year: int, month: int, day: int): pass