code: function extractHexByteSlice (slotValue, byteLength, offsetFromLSB) {
    var offset = slotValue.length - 2 * offsetFromLSB - 2 * byteLength
    return slotValue.substr(offset, 2 * byteLength)
  }
docs: @returns a hex encoded byte slice of length @arg byteLength from inside @arg slotValue.
  
  @param {String} slotValue  - hex encoded value to extract the byte slice from
  @param {Int} byteLength  - Length of the byte slice to extract
  @param {Int} offsetFromLSB  - byte distance from the right end slot value to the right end of the byte slice