@NotNull
  @Override
  public String getInternalCanonicalText() {
    return "[" +
           (myLeft == null ? PsiKeyword.NULL : myLeft.getInternalCanonicalText()) +
           ".." +
           (myRight == null ? PsiKeyword.NULL : myRight.getInternalCanonicalText()) +
           "]";
  }
@NotNull
  @Override
  public String getInternalCanonicalText()