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contracts...MyToken.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";

contract MyToken is Initializable, ERC721Upgradeable, OwnableUpgradeable, UUPSUpgradeable {
    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor() {
        _disableInitializers();
    }

    function initialize() initializer public {
        __ERC721_init("MyToken", "MTK");
        __Ownable_init();
        __UUPSUpgradeable_init();
    }

    function _authorizeUpgrade(address newImplementation)
        internal
        onlyOwner
        override
    {}
}