Driver code
if __name__ == " _ _ main _ _ " : NEW_LINE INDENT string = "2 ▁ + ▁ 5 ▁ + ▁ 3 ▁ + ▁ 1 ▁ = ▁ 11" ; NEW_LINE if ( isValid ( string ) ) : NEW_LINE INDENT print ( " Valid " ) ; NEW_LINE DEDENT else : NEW_LINE INDENT print ( " Invalid " ) ; NEW_LINE DEDENT DEDENT