input: Write a function to create a Python web application for a car insurance calculator using Flask. The application should have an endpoint `/calculate` where the user can send a POST request with JSON data containing fields like age, gender, and car_model. The function should return a calculated insurance price. If the input data is incomplete, the function should return an appropriate error message.
  
  
  assert calculate({'age': 30, 'gender': 'male', 'car_model': 'sedan'})=={'insurance_price': 0.00}
  assert calculate({'age': 25, 'gender': 'female', 'car_model': 'SUV'})=={'insurance_price': 0.00}
  assert calculate({'age': 20})=={'error': 'Incomplete input data'}
  assert calculate({'gender': 'other', 'car_model': 'sports car'})=={'error': 'Incomplete input data'}
  
output: def calculate(data):
      required_fields = ['age', 'gender', 'car_model']
      for field in required_fields:
          if field not in data:
              return {'error': 'Incomplete input data'}
      return {'insurance_price': 0.00}