contract AddressSet {
  /**
   * Check whether address set contains given address.
   *
   * @param _address address to check
   * @return true if address set contains given address, false otherwise
   */
  function contains (address _address) public view returns (bool);
}
/**
 * Address Set smart contract interface.
 */
function contains (address _address) public view returns (bool);
/**
 * Check whether address set contains given address.
 *
 * @param _address address to check
 * @return true if address set contains given address, false otherwise
 */