我试图通过请求进行交易，但收到错误400。我知道此错误意味着请求不正确，但我不知道我做错了什么。

import requests
import time
import hashlib
import hmac

# Set the base API URL for the Binance Testnet
BASE_URL = "https://testnet.binancefuture.com"

# Set the endpoint for placing an order on the futures exchange
ENDPOINT = "/fapi/v1/order"

# Set the API key and secret key as headers for the HTTP request
API_KEY = ""
API_SECRET = ""
headers = {
    "Content-Type": "application/json",
    "X-MBX-APIKEY": API_KEY
}

# Define the parameters for the order
symbol = "EOSUSDT"
side = "BUY"
type = "MARKET"
time_in_force = "GTC"
quantity = 20

# Define the payload for the HTTP request
payload = {
    "symbol": symbol,
    "side": side,
    "type": type,
    "timeInForce": time_in_force,
    "quantity": quantity,
    "timestamp": int(time.time() * 1000)
}

# Generate the signature for the request
query_string = "&".join([f"{k}={v}" for k, v in payload.items()])
signature = hmac.new(API_SECRET.encode(), query_string.encode(), hashlib.sha256).hexdigest()

# Add the signature to the request headers
headers["X-MBX-SIGNATURE"] = signature

# Send the HTTP request using the requests.post() function
response = requests.post(BASE_URL + ENDPOINT, headers=headers, json=payload)

# Check the response from the server to see if the order was successful
if response.status_code == 200:
    print("Order placed successfully!")
else:
    print("Order placement failed. Error code:", response.status_code)

我添加了对符号和时间戳参数的检查，但它没有给予结果。