File: contracts/protocol/ParticlePositionManager.sol

 98:    function onERC721Received(
...
103:    ) external override returns (bytes4) {
104:        if (msg.sender == Base.UNI_POSITION_MANAGER_ADDR) {
			// ... add liq position
109:        }
			// all ERC721s are accepted
110:        return this.onERC721Received.selector;
111:    }
