docs: public static Value valueFromAst(String astLiteral) {
          // we use the parser to give us the AST elements as if we defined an inputType
          String toParse = "input X { x : String = " + astLiteral + "}";
          try {
              Document doc = new Parser().parseDocument(toParse);
              InputObjectTypeDefinition inputType = (InputObjectTypeDefinition) doc.getDefinitions().get(0);
              InputValueDefinition inputValueDefinition = inputType.getInputValueDefinitions().get(0);
              return inputValueDefinition.getDefaultValue();
          } catch (Exception e) {
              return Assert.assertShouldNeverHappen("valueFromAst of '%s' failed because of '%s'", astLiteral, e.getMessage());
          }
      }