pragma solidity ^0.6.2; import "./IERC721.sol"; /** * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension * @dev See https://eips.ethereum.org/EIPS/eip-721 */ interface IERC721Enumerable is IERC721 { function totalSupply() external view returns (uint256); function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId); function tokenByIndex(uint256 index) external view returns (uint256); }