fix(contains): check if expression is a fucntion
fix(contains): check if expression is a fucntion

dimitriwalters/angular-filter,gilluminate/angular-filter,Jeremy017/angular-filter,a8m/angular-filter,darryldecode/angular-filter,Jandalf/angular-filter,mattspaulding/angular-filter,noahxinhao/angular-filter,seawenzhu/angular-filter,aidenzou/angular-filter,mallowigi/angular-filter,danrevah/angular-filter,jlsuarezs/angular-filter,tpsumeta/angular-filter,nagyistoce/angular-filter,dryvenn/angular-filter