code: public static String assertValidName(String name) {
          if (name != null && !name.isEmpty() && name.matches("[_A-Za-z][_0-9A-Za-z]*")) {
              return name;
          }
          throw new AssertException(String.format(invalidNameErrorMessage, name));
      }
docs: Validates that the Lexical token name matches the current spec.
  currently non null, non empty,
  
  @param name - the name to be validated.
  
  @return the name if valid, or AssertException if invalid.