//Write your own contracts here. Currently compiles using solc v0.4.15+commit.bbb8e64f. pragma solidity ^0.4.18; contract minting{ uint dnaDigits = 16; uint dnaModulus = 10 ** dnaDigits; struct Robot{ string name; uint32 dna; uint level; } Robot public robots; function mint(string memory name, uint32 dna) private { } function generateDna(){ } } contract breeding is minting{ function breedTwoNFTS(uint _dna1, uint _dna2, uint breedingTime) internal returns (uint){ bool breedingStatus = (breedingTime <=now); uint childDna; if(breedingSatus){ childDna = (_dna1 + _dna2)/2; } returns childDna; } } 0.4.18