diff -r 670b7d089699 -r 509d49c493c0 src/goodjava/xml/XmlElement.java
--- a/src/goodjava/xml/XmlElement.java	Mon Apr 13 22:00:40 2020 -0600
+++ b/src/goodjava/xml/XmlElement.java	Mon Apr 13 22:16:59 2020 -0600
@@ -41,21 +41,20 @@
 		if( content instanceof String ) {
 			String s = (String)content;
 			sb.append(s);
-		} else if( content instanceof XmlElement[] ) {
+		} else {
 			XmlElement[] elements = (XmlElement[])content;
 			sb.append( '\n' );
 			for( XmlElement element : elements ) {
 				element.toString(sb,indented+1);
 			}
 			indent(sb,indented);
-		} else
-			throw new RuntimeException();
+		}
 		sb.append( "</" );
 		sb.append( name );
 		sb.append( ">\n" );
 	}
 
-	private void indent(StringBuilder sb,int indented) {
+	private static void indent(StringBuilder sb,int indented) {
 		for( int i=0; i<indented; i++ ) {
 			sb.append('\t');
 		}