input: Write a function to create a simple Python web application for a car insurance calculator using Flask. The application should have an endpoint '/calculate' that accepts POST requests with JSON data containing the user's age, gender, and car model, and returns the calculated insurance price.
  
  from flask import Flask, request, jsonify
  
  app = Flask(__name__)
  
  @app.route('/calculate', methods=['POST'])
  def calculate():
      data = request.get_json()
      age = data['age']
      gender = data['gender']
      car_model = data['car_model']
      insurance_price = 0.00  # Placeholder for calculation
      return jsonify({'insurance_price': insurance_price})
  
  assert app.calculate([{'age': 30, 'gender': 'male', 'car_model': 'Sedan'}])=={'insurance_price': 0.00}
  assert app.calculate([{'age': 25, 'gender': 'female', 'car_model': 'SUV'}])=={'insurance_price': 0.00}
  assert app.calculate([])=={'insurance_price': 0.00}
  app.run(host='0.0.0.0', port=8006)
output: 
  def calculate():
      data = request.get_json()
      age = data['age']
      gender = data['gender']
      car_model = data['car_model']
      insurance_price = 0.00  # Placeholder for calculation
      return jsonify({'insurance_price': insurance_price})
  