TypeError can be thrown as "headHop" might be null or undefined

[BillHodghead]

TypeError can be thrown as "headHop" might be null or undefined in src/lib/core.js, on line 146

const tailQuote = yield sourceClient._getQuote(intermediateConnector, omitUndefined({
  source_address: intermediateConnector,
  source_amount: query.sourceAmount === undefined
    ? undefined
    : (yield this._roundDown(**headHop**.destinationLedger, headHop.destinationAmount)),