Driver code
if __name__ == " _ _ main _ _ " : NEW_LINE INDENT S = " permanent " NEW_LINE T = " pergament " NEW_LINE n = len ( S ) NEW_LINE if ( S == " " or T == " " ) : NEW_LINE INDENT print ( " Required ▁ string ▁ is ▁ empty . " ) NEW_LINE DEDENT else : NEW_LINE INDENT Swap ( S , T , n ) NEW_LINE DEDENT DEDENT