code: async function extractHexValue (location, storageResolver, byteLength) {
    var slotvalue
    try {
      slotvalue = await readFromStorage(location.slot, storageResolver)
    } catch (e) {
      return '0x'
    }
    return extractHexByteSlice(slotvalue, byteLength, location.offset)
  }
docs: @returns a hex encoded storage content at the given @arg location. it does not have Ox prefix but always has the full length.
  
  @param {Object} location  - object containing the slot and offset of the data to extract.
  @param {Object} storageResolver  - storage resolver
  @param {Int} byteLength  - Length of the byte slice to extract