I am trying to implement bdd test cases for flask application api end points. i am getting following error.

**You can implement step definitions for undefined steps with these snippets:

@then(u’the response should contain JSON with “result” equal to 12′)
def step_impl(context):
raise NotImplementedError(u’STEP: Then the response should contain JSON with “result” equal to 12′)**

from flask import Flask, jsonify, request

app = Flask(__name__)

@app.route('/api/greet', methods=['GET'])
def greet():
    name = request.args.get('name', 'World')
    return jsonify(message=f"Hello, {name}!")

@app.route('/api/add', methods=['POST'])
def add():
    data = request.get_json()
    result = data['a'] + data['b']
    return jsonify(result=result)

@app.route('/api/subtract', methods=['POST'])
def subtract():
    data = request.get_json()
    result = data['a'] - data['b']
    return jsonify(result=result)

if __name__ == '__main__':
    app.run(host='0.0.0.0')

Feature file:

Feature: Flask API Endpoints
  Scenario: Greet endpoint with query parameter
    Given the API is running
    When I send a GET request to "/api/greet" with query parameter "name" set to "Alice"
    Then the response status code should be 200
    And the response should contain JSON with "message" equal to "Hello, Alice!"
  Scenario: Add endpoint with JSON payload
    Given the API is running
    When I send a POST request to "/api/add" with JSON payload:
      """
      {
        "a": 5,
        "b": 7
      }
      """
    Then the response status code should be 200
    And the response should contain JSON with "result" equal to 12
  Scenario: Subtract endpoint with JSON payload
    Given the API is running
    When I send a POST request to "/api/subtract" with JSON payload:
      """
      {
        "a": 10,
        "b": 4
      }
      """
    Then the response status code should be 200
    Then the response should contain JSON with "result" equal to 6

Step definition:

from behave import given, when, then
import requests
import json
from flask import Flask
import threading
import time

# Import the Flask app
from app import app

# Helper function to run the Flask app in a separate thread
def start_flask_app():
    app.run(port=5000)

# Start the Flask app in a separate thread
thread = threading.Thread(target=start_flask_app)
thread.daemon = True
thread.start()

# Wait a bit for the server to start
time.sleep(1)

@given('the API is running')
def step_impl(context):
    response = requests.get('http://localhost:5000/api/greet')
    assert response.status_code == 200

@when('I send a GET request to "{endpoint}" with query parameter "name" set to "{name}"')
def step_impl(context, endpoint, name):
    context.response = requests.get(f'http://localhost:5000{endpoint}', params={'name': name})

@when('I send a POST request to "{endpoint}" with JSON payload')
def step_impl(context, endpoint):
    print("ENDPOINT:{}".format(endpoint))
    payload = json.loads(context.text)
    context.response = requests.post(f'http://localhost:5000{endpoint}', json=payload)

@then('the response status code should be {status_code:d}')
def step_impl(context, status_code):
    assert context.response.status_code == status_code

# @then('the response should contain JSON with "{key}" equal to "{value}"')
# def step_impl(context, key, value):
#     response_json = context.response.json()
#     if key.isdigit():
#         assert response_json[key] == int(value)
#     else:
#         assert response_json[key] == value

@then('the response should contain JSON with "{key}" equal to "{value}"')
def step_impl(context, key, value):
    response_json = context.response.json()
    # Convert value to the appropriate type (e.g., int or str)
    if value.isdigit():
        value = int(value)
    else:
        try:
            value = float(value)
        except ValueError:
            pass
    assert response_json[key] == value, f"Expected {key} to be {value}, but got {response_json[key]}"

for some reason it is not able to read.
@then(‘the response should contain JSON with “{key}” equal to “{value}”‘)
and I am getting undefined step error