 if (msg.sender == address(this) || msg.sender == address(s.LIEN_TOKEN)) {
	revert InvalidCollateral();
  }

  _mint(from_, collateralId);

  s.idToUnderlying[collateralId] = Asset({
	tokenContract: msg.sender,
	tokenId: tokenId_
  });

  emit Deposit721(msg.sender, tokenId_, collateralId, from_);
  return IERC721Receiver.onERC721Received.selector;
