anchor.diff:      // Remove added values returning reserved words back to inital state.
       NHol.printer.unreserve_words ["TeSt"; "two words"]
       let removeResult = NHol.printer.reserved_words()
  +//    printfn "Reserved words - expected: %A" reserved_words_initial
  +//    printfn "Reserved words - result: %A" removeResult
       NUnit.Framework.CollectionAssert.AreEquivalent(removeResult, reserved_words_initial)
   
   (* is_reserved_word  tests *)
  
positive.code:         "function";
          "->";
          "when";
          "TeSt";
          "two words"
          ]
  
negative.code:     // Add some values.
      NHol.printer.reserve_words ["TeSt"; "two words"]
      let addResult = NHol.printer.reserved_words()
  //    printfn "Reserved words - expected: %A" reserved_words_added
  //    printfn "Reserved words - result: %A" addResult
      NUnit.Framework.CollectionAssert.AreEquivalent(addResult, reserved_words_added)
  
      // Test for one of the added values.
  