pyth-network_pyth-crosschain/ethereum/contracts/wormhole-receiver/ReceiverImplementation.sol

// contracts/Implementation.sol
// SPDX-License-Identifier: Apache 2

pragma solidity ^0.8.0;
pragma experimental ABIEncoderV2;

import "./ReceiverGovernance.sol";

import "@openzeppelin/contracts/proxy/ERC1967/ERC1967Upgrade.sol";

contract ReceiverImplementation is ReceiverGovernance {

    modifier initializer() {
        address implementation = ERC1967Upgrade._getImplementation();

        require(
            !isInitialized(implementation),
            "already initialized"
        );

        setInitialized(implementation);

        _;
    }

    fallback() external payable {revert("unsupported");}

    receive() external payable {revert("the Wormhole Receiver contract does not accept assets");}
}