contract IRequiredAsset {

    /// @dev Check balanceOf owner
    /// @param owner The address from which the balance will be retrieved
    /// @return Balance of owner
    function balanceOf(address owner)
        external
        view
        returns (uint256);

    /// @dev Check ownerOf tokenId
    /// @param tokenId The token id from which the ownership will be checked
    /// @return Owner address of tokenId
    function ownerOf(uint256 tokenId)
        external
        view
        returns (address);
}
/*
 
 Copyright 2018 ZeroEx Intl.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
 http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 
 */
function ownerOf(uint256 tokenId)
    external
    view
    returns (address);

/// @dev Check ownerOf tokenId
/// @param tokenId The token id from which the ownership will be checked
/// @return Owner address of tokenId