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contracts...subquest-erc-721.sol

pragma solidity >=0.6.0 <0.8.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v3.4/contracts/token/ERC721/ERC721.sol";

contract MyNft is ERC721 {
    string NAME = "Abstract Collectibles";
    string SYMBOL = "ABS";

    uint256 private _tokenId;
    address private _owner;

    constructor() public ERC721(NAME, SYMBOL) {
        _owner = msg.sender;
    }

    function mintCollectible(address receiver, string memory tokenURI) external returns (uint256) {
        // only owner should be able to mint new NFTs
        assert(msg.sender == _owner);
        
        // unique id for nft in your collection
        _tokenId += 1;

        // finally mint out NFT to receiver
        _mint(receiver, _tokenId);
        
        // set tokenURI for plugging in our metadata to NFT
        _setTokenURI(_tokenId, tokenURI);

        return _tokenId;
    }
}