code: def spendables_for_address(self, address):
          
          URL = "%s/addr/%s/utxo" % (self.base_url, address)
          r = json.loads(urlopen(URL).read().decode("utf8"))
          spendables = []
          for u in r:
              coin_value = btc_to_satoshi(str(u.get("amount")))
              script = h2b(u.get("scriptPubKey"))
              previous_hash = h2b_rev(u.get("txid"))
              previous_index = u.get("vout")
              spendables.append(Tx.Spendable(coin_value, script, previous_hash, previous_index))
          return spendables
docs: Return a list of Spendable objects for the
          given bitcoin address.