Search return type does not include error type

[sspenst]

Search currently returns the type for a result, but does not include a union with an error type.

For example, if search is called with an empty query string, the return type is:

{
  "error" : {
    "status" : 400,
    "message" : "No search query"
  }
}

But this is not represented in the possible return types from running search() and should be added