NFTDropMarketCore.sol

// SPDX-License-Identifier: MIT OR Apache-2.0

pragma solidity ^0.8.12;

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";

/**
 * @title A place for common modifiers and functions used by various market mixins, if any.
 * @dev This also leaves a gap which can be used to add a new mixin to the top of the inheritance tree.
 */
abstract contract NFTDropMarketCore {
  /**
   * @notice This empty reserved space is put in place to allow future versions to add new
   * variables without shifting down storage in the inheritance chain.
   * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
   */
  uint256[1000] private __gap;
}