How to use the @0x/contracts-erc20.artifacts.WETH9 function in @0x/contracts-erc20

const erc721 = await ERC721TokenContract.deployFrom0xArtifactAsync(
            ERC721Artifacts.ERC721Token,
            environment.provider,
            txDefaults,
            ERC721Artifacts,
        );

        const erc1155 = await ERC1155Contract.deployFrom0xArtifactAsync(
            ERC1155Artifacts.ERC1155,
            environment.provider,
            txDefaults,
            ERC1155Artifacts,
        );

        const weth = await WETH9Contract.deployFrom0xArtifactAsync(
            ERC20Artifacts.WETH9,
            environment.provider,
            txDefaults,
            ERC20Artifacts,
        );

        const zrx = await ZRXTokenContract.deployFrom0xArtifactAsync(
            ERC20Artifacts.ZRXToken,
            environment.provider,
            txDefaults,
            ERC20Artifacts,
        );

        return {
            erc1155,
            erc20,
            erc721,