@Nullable
  default PyAstExpression getTypeExpression() {
    PsiElement child = getLastChild();
    while (child != null && !(child instanceof PyAstExpression)) {
      if (child instanceof PsiErrorElement) return null;
      child = child.getPrevSibling();
    }
    return (PyAstExpression)child;
  }
@Nullable
  default PyAstExpression getTypeExpression()