Fix merge glitch.

Doc/tutorial/introduction.rst

@@ -548,7 +548,7 @@ series as follows::
    ... # the sum of two elements defines the next
    ... a, b = 0, 1
    >>> while b < 10:
-   ...       print b
+   ...     print(b)
    ...     a, b = b, a+b
    ... 
    1