Can't get post request error 400 Bad Request

Alpaca Integration Applications App-Integration
1

I want to get access token Build Your Own Brokerage With FastAPI - Part 1 in the last sessions.

when I try

import requests

url = "http://127.0.0.1:8000/platform/signup/"

payload = {
  "email": "testing@test.com",
  "password": "password"
}

headers = {
  "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

if response.status_code == 200:
  # Successful request
  data = response.json()
  access_token = data["access_token"]
  refresh_token = data["refresh_token"]
  cognito_user_id = data["cognito_user_id"]
  print(f"Access token: {access_token}")
  print(f"Refresh token: {refresh_token}")
  print(f"Cognito user ID: {cognito_user_id}")
else:
  # Handle error
  print(f"Request failed with status code {response.status_code}")

it show error
"POST /platform/signup/ HTTP/1.1" 400 Bad Request
instead of Response:

{
  "access_token": "[OMITTED]",
  "refresh_token": "[OMITTED]",
  "cognito_user_id": "[OMITTED]"
}

what should I do ??