指値(メイカー)で売り、成行(テイカー)で買ったときの損益計算をするプログラムを作りました

import ccxt
import time
from pprint import pprint
import requests
import json
endPoint = 'https://api.coin.z.com/public'
path     = '/v1/orderbooks?symbol=BTC'
order_amount = 1 #注文数量
#GMO
def BuyPriceOrder():
	response = requests.get(endPoint + path)
	json_data = response.json()
	i = 0
	size_sum = 0
	price_sum = 0
	taker_price = 0
	while size_sum < order_amount:
		size_sum = size_sum + float(json_data["data"]["asks"][i]["size"])
		price_sum = price_sum + float(json_data["data"]["asks"][i]["price"])
		taker_price = taker_price + float(json_data["data"]["asks"][i]["price"]) * (float(json_data["data"]["asks"][i]["size"]))
		i = i + 1
	delta = size_sum - order_amount
	return taker_price - float(json_data["data"]["asks"][i-1]["price"]) * delta
#bitbank
def SellLimitOrder():
	exchange = eval('ccxt.' + 'bitbank' + '()')
	orderbook = exchange.fetch_order_book ('BTC/JPY')
	return order_amount * orderbook['asks'][0][0]     #指値でMaker取引をするためbidではなくask(売り注文)の値を取得
while 1:
	buy_price_order = BuyPriceOrder()
	sell_limit_order = SellLimitOrder()
	price_fee = buy_price_order * 0.0005 #GMO taker fee
	limit_fee = sell_limit_order * -0.0002 #bitbank maker fee
	print('テイカー手数料は',price_fee,'円')
	print('メイカー手数料は',limit_fee,'円')
	print(buy_price_order,'円で買って(テイカー)')
	print(sell_limit_order,'円で売れば(メイカー)')
	print(sell_limit_order - buy_price_order - price_fee - limit_fee,'円の利益！')
	time.sleep(5)