flask_boilerplate.py

server.py

from flask import (
  Flask,
  request
)

app = Flask(__name__)

library = {}

@app.route('/book', methods=['POST'])
def create_book():
    data = request.get_json()
    library[data['title']] = data
    return library[data['title']], 201

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