How to add contract input (not complex) to the multiple business object via operations ?

Hello, I have a business obj named "gunluk"(multiple). My contract is "gunlukInput" (no complex). I have a human task that contains a simple form. I am trying to add formInput elements to the business obj(gunluk) via operations (add). But I have an error : Caused by: groovy.lang.MissingPropertyException: No such property: aciklama for class: java.util.HashMap$Node
My Code :
def gunlukList = []
gunlukInput.each{
currentGunlukInput ->
def gunlukVar = new com.company.model.Gunluk()
gunlukVar.aciklama = currentGunlukInput.aciklama
gunlukVar.zorluklar = currentGunlukInput.zorluklar
gunlukVar.yapilanIs = currentGunlukInput.yapilanIs
gunlukList << gunlukVar

}
return gunlukList
Could you help me? When I change contract to complex It works. But my contract shouldn't be complex.