code: function fromRpcSig(flatSig) {
      const expandedSig = ethutil.fromRpcSig(flatSig);
  
      return {
          s: ethutil.bufferToHex(expandedSig.s),
          r: ethutil.bufferToHex(expandedSig.r),
          v: expandedSig.v
      };
  }
docs: Takes a flat format RPC signature and returns it in expanded form, with
  s, r in hex string form, and v a number
  @param {String} flatSig Flat form signature
  @returns {Object} Expanded form signature