How can ArcGIS labels use a different expression if attribute is null=?iso-8859-1?Q?=3F_=96_gis.stackexchange.com?=

How can ArcGIS labels use a different expression if attribute is null? –
gis.stackexchange.com

I am using an expression to label features by concatenating two attributes
in ArcMap. It works like this: <attribute_1>+" "+<attribute_2>
Unfortunately when either attribute is Null the …