remove sentence

docs/spec/annotations.rst

@@ -355,9 +355,7 @@ In most cases the first argument of instance and class methods
 If the argument is not annotated, then for instance methods it is
 assumed to have the type of the containing class or :ref:`Self
 <self>`, and for class methods the type object type corresponding to
-the containing class object or ``type[Self]``. In a class method, the
-precise type of the first argument cannot be represented using the
-available type notation.
+the containing class object or ``type[Self]``.
 
 In addition, the first argument in an instance method can be annotated
 with a type variable. In this case the return type may use the same