How to start a process from SAIL Interface

Trying to start a process from SAIL interface with below SAIL code, but getting below error with Dictionary. Please advise how to pass the array values in code in dictionary form. Does it need a CDT type? Is CDT a Dictionary?

a!startProcess(
processModel: cons!NSA_StartCreateRequest_PM_Cons,
processParameters: {
ri!NSARequest,
ri!cancel,
null
},
onSuccess: a!save(ri!NSARequest,null),
onError: a!save(ri!NSARequest,null)
)

Error:

Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error: An error occurred while executing a save: Expression evaluation error at function a!startProcess [line 231]: Could not cast from List of Variant to Dictionary. Details: CastInvalid