#you can chagne the method  spendables_for_address in pycoin.services.blockcypher  with this
def spendables_for_address(self, address,amount = None ):
        """
        Return a list of Spendable objects for the
        given bitcoin address.
        """
        """simple output like pycoin without amount"""
        if amount is None :
            spendables = []
            url_append = "?unspentOnly=true&token=%s&includeScript=true" % self.api_key
            url = self.base_url("addrs/%s%s" % (address, url_append))
            result = json.loads(urlopen(url).read().decode("utf8"))
            for txn in result.get("txrefs", []):
                coin_value = txn.get("value")
                script = h2b(txn.get("script"))
                previous_hash = h2b_rev(txn.get("tx_hash"))
                previous_index = txn.get("tx_output_n")
                spendables.append(Spendable(coin_value, script, previous_hash, previous_index))
            return spendables
        """"for the specified amount it will return an list with
        total spendable and total amount"""
        """
        example  out= spendables_for_address('address',11)
        spendable = out[0]
        total = out[1]
        change = total-fee-amount
        """

        else :
            spendables = []
            url_append = "?unspentOnly=true&token=%s&includeScript=true" % self.api_key
            url = self.base_url("addrs/%s%s" % (address, url_append))
            result = json.loads(urlopen(url).read().decode("utf8"))
            total_amount = 0
            list_spend = result.get("txrefs", [])
            if len(list_spend) == 0:
                raise Exception("No spendable outputs found")
            unspents = sorted(list_spend, key=lambda d: d['value'], reverse = True)
            for txn in unspents:
                coin_value = txn.get("value")
                total_amount = total_amount + coin_value
                script = h2b(txn.get("script"))
                previous_hash = h2b_rev(txn.get("tx_hash"))
                previous_index = txn.get("tx_output_n")
                spendables.append(Spendable(coin_value, script, previous_hash, previous_index))
                if total_amount > amount :
                    break
            return [spendables, total_amount]