Strings in Python are actually objects and contain several methods that can operate on their contents. For example they contain a strip method:

$>>s=$quad abcd

$>>s.$strip$()$

'abcd'

In

strings.py$,$ use the replace and upper methods, described in the String Methods Reference to display a string in all uppercase, and with the spaces replaced by underscores:

Enter a string: A string I entered

Uppercase: A STRING I ENTERED

Underscores: A$\_$string$\_$I$\_$entered