NullReferenceException when using setter-only property

[radverg]

Describe the bug
My datamodel contained a property with only purpose to transform value and save it to other property/field. Therefore, the property had only a setter defined. The library throws NullReferenceException (wrapped in YamlException) when attempting to deserialize into such model. Such exception tells nothing about what is happening and took me hours to figure it out.

To Reproduce
Create simple class containing property with defined setter, but not getter. Try to deserialize yaml into the class.