File: contracts/proxies/Vault721.sol

  /**
   * @dev generate URI with updated vault information
   */
  function tokenURI(uint256 _safeId) public view override returns (string memory uri) {
    // @audit should throw if safeId does not exist according to the ERC721-Metadata specification
    uri = nftRenderer.render(_safeId);
  }
  /**
   * @dev generate URI with updated vault information
   */
  function tokenURI(uint256 _safeId) public view override returns (string memory uri) {
+++ _requireMinted(_safeId);
    uri = nftRenderer.render(_safeId);
  }
