The fallback(handler) method let’s the user define a method that is invoked whenever the initial method dispatch fails. Here is an example of how to define a fallback.

let dynob = DynamicObject():
  fallback(|this, method, args...| {
    return "Dispatch failed for method: " + method + ", with args: " + args: asList(): join(" ")
  })

println(dynob: casperGetter())
println(dynob: casperMethod("foo", "bar"))

Dispatch failed for method: casperGetter, with args:
Dispatch failed for method: casperMethod, with args: foo bar