Remove redundant information.
diff --git a/Doc/library/constants.rst b/Doc/library/constants.rst
index b69d117..51a1c26 100644
--- a/Doc/library/constants.rst
+++ b/Doc/library/constants.rst
@@ -38,9 +38,9 @@
 .. data:: __debug__
 
    This constant is true if Python was not started with an :option:`-O` option.
-   Assignments to :const:`__debug__` are illegal and raise a :exc:`SyntaxError`.
    See also the :keyword:`assert` statement.
 
+
 .. note::
 
    The names :data:`None`, :data:`False`, :data:`True` and :data:`__debug__`