code: func (h *HashCache) GetSigHashes(txid *chainhash.Hash) (*TxSigHashes, bool) {
  	h.RLock()
  	item, found := h.sigHashes[*txid]
  	h.RUnlock()
  
  	return item, found
  }
docs: // GetSigHashes possibly returns the previously cached partial sighashes for
  // the passed transaction. This function also returns an additional boolean
  // value indicating if the sighashes for the passed transaction were found to
  // be present within the HashCache.