Usage
testPlatykurtic(
  object,
  errormsg = paste(object$short_name, "is not platykurtic")
)checkPlatykurtic(
  object,
  errormsg = paste(object$short_name, "is not platykurtic")
)
assertPlatykurtic(
  object,
  errormsg = paste(object$short_name, "is not platykurtic")
)