That's my first exercise on I/O!

shellf.py

def createBook(title,author,year):
  outFile = open('database.txt', 'wt')
  outFile.write("[book]\n")
  outFile.write("title: " + title + "\n")
  outFile.write("author: " + author + "\n")
  outFile.write("year: " + year + "\n")
  outFile.close()

print("Welcome to Shellf!")
print("Answer the questions to add your book do the database.")
title = input("Title: ")
author = input("Author: ")
year = input("Year: ")
print("Adding book...")
createBook(title,author,year)