Get prices from the NEST Oracle and then provide the prices for free

NESTBootleg.sol

import 'https://raw.githubusercontent.com/NEST-Protocol/NEST-Oracle-V3.5/main/contracts/iface/INestQuery.sol';
pragma solidity ^0.6.12;

contract NESTBootleg {
    
    struct Price {
        uint ethAmount;
        uint erc20Amount;
        uint blockNum; 
    }
    
   mapping(address => mapping(uint => Price)) prices; 
   
   INestQuery iNestQuery;
   
   constructor(_nestQueryAddress) {
       iNestQuery = INestQuery(_nestQueryAddress); 
   }
   
   function updatePrice(address token) public payable {
       (uint ethAmount, uint erc20Amount, uint blockNum) = iNestQuery.query(token, msg.sender); 
       Price newPrice = Price(ethAmount, erc20Amount, blockNum); 
       prices[token][blockNum] = newPrice; 
   }
   
   function getPrice(address token, uint blockNum) public view returns(Price) {
       return prices[token][blockNum];
   }
   
}