improved readability

Co-authored-by: CyrilFerlicot <cyril@ferlicot.me>

Author: Joshua-Dias-Barreto

src/DataFrame/DataFrame.class.st

@@ -2454,10 +2454,7 @@ DataFrame >> toString [
 
 	dataFrame columnNames withIndexDo: [ :columnName :index |
 		| paddedColumnName |
-		paddedColumnName := (columnName isString
-			                     ifFalse: [ columnName asString ]
-			                     ifTrue: [ columnName ]) padRightTo:
-			                    (columnWidths at: index).
+		paddedColumnName := columnName asString padRightTo: (columnWidths at: index).
 		stringTable nextPutAll: paddedColumnName , '  ' ].
 	stringTable cr.