import { BigNumber } from "https://deno.land/x/web3@v0.11.1/types/bignumber.d.ts";
Returns a BigNumber whose value is the sum of the arguments.
The return value is always exact and unrounded.
x = new BigNumber('3257869345.0378653')
BigNumber.sum(4e9, x, '123456789.9') // '7381326134.9378653'
arr = [2, new BigNumber(14), '15.9999', 12]
BigNumber.sum.apply(null, arr) // '43.9999'