public @Nullable String computeTemplateKey(@NotNull CustomTemplateCallback callback) {
    Editor editor = callback.getEditor();
    int currentOffset = editor.getCaretModel().getOffset();
    int startOffset = editor.getDocument().getLineStartOffset(editor.getCaretModel().getLogicalPosition().line);
    String key = computeKey(editor.getDocument().getCharsSequence().subSequence(startOffset, currentOffset));
    return !StringUtil.isEmpty(key) && ZenCodingTemplate.checkTemplateKey(key, callback, this) ? key : null;
  }
public @Nullable String computeTemplateKey(@NotNull CustomTemplateCallback callback)