write to csv.py

import os
import csv 
from datetime import datetime
import decimal
from decimal import Decimal

data = ''
def calcPrice(data):
    ReferenceID = input("Reference ID: ")
    clientName = input("Client Name: ")
    date = input("Date (format - dd/mm/yyyy): ")
    timeFrom = input("From (time in 24hrs e.g 0900): ")
    timeTo = input("To (time in 24hrs e.g 1330): ")
    
    dtFrom = datetime.strptime(timeFrom,"%H%M") 
    dtTo = datetime.strptime(timeTo,"%H%M") 

    rate = 5
   
    diff = decimal.Decimal((dtTo - dtFrom).total_seconds()) / decimal.Decimal(3600)
    diff = round (diff, 2)

    price = rate * diff
    data = {'ReferenceID': ReferenceID, 
            'clientName': clientName, 
            'Date': date,
            'From':timeFrom,
            'To':timeTo,
            'Rate':rate,
            'Price':price}
    
    
    fieldnames = ["ReferenceID","clientName","Date","From","To","Rate","Price"]
    with open(r'records21.csv', 'a') as csvfile:
        writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
        writer.writeheader()
        writer.writerow(data)
        


    return