How to validate and return the name of empty variables

Summary:

Validate that there are no null input parameters and, if necessary, identify the name of the null parameter to return it in a response

Content (required):

Hi experts,

I am working on an integration which has 8 input parameters, I have to create a validation of those parameters to verify that none of them come null but if it happens that some parameter is null, then, identify which variable it is to be able to notify in the response of the integration which variables are the ones that are empty for example

integration receives:

var1 = Oliver

var2 =

var3 = Harry

var4 = Thomas