contract Pausable is Ownable {
  event Paused(address account);
  event Unpaused(address account);

  bool private _paused;

  constructor() internal {
    _paused = false;
  }

  /**
   * @return true if the contract is paused, false otherwise.
   */
  function paused() public view returns(bool) {
    return _paused;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!_paused);
    _;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
  modifier whenPaused() {
    require(_paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() public onlyOwner whenNotPaused {
    _paused = true;
    emit Paused(msg.sender);
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() public onlyOwner whenPaused {
    _paused = false;
    emit Unpaused(msg.sender);
  }
}
/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
function paused() public view returns(bool) {
  return _paused;
}

/**
 * @return true if the contract is paused, false otherwise.
 */