contract OrisSpace {
  /**
   * Start Oris Space smart contract.
   *
   * @param _returnAmount amount of tokens to return to message sender.
   */
  function start (uint256 _returnAmount) public;
}
function start (uint256 _returnAmount) public;

/**
 * Start Oris Space smart contract.
 *
 * @param _returnAmount amount of tokens to return to message sender.
 */