tornado-trees/contracts/AdminUpgradeableProxy.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

import "@openzeppelin/contracts/proxy/TransparentUpgradeableProxy.sol";

/**
 * @dev TransparentUpgradeableProxy where admin is allowed to call implementation methods.
 */
contract AdminUpgradeableProxy is TransparentUpgradeableProxy {
  /**
   * @dev Initializes an upgradeable proxy backed by the implementation at `_logic`.
   */
  constructor(address _logic, address _admin, bytes memory _data) public payable TransparentUpgradeableProxy(_logic, _admin, _data) {}

  /**
   * @dev Override to allow admin access the fallback function.
   */
  function _beforeFallback() internal override {}
}