Fix documentation for input and output tutorial (GH-8231)

lysnikolaou · Mariatta · commit 9cffdbffc3b2 · 2018-07-10T17:11:34.000-07:00
The ValueError message ends with a period.
diff --git a/Doc/tutorial/inputoutput.rst b/Doc/tutorial/inputoutput.rst
@@ -338,7 +338,7 @@ automatically fail. ::
    >>> f.read()
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
-   ValueError: I/O operation on closed file
+   ValueError: I/O operation on closed file.
 
 
 .. _tut-filemethods:
