def flask(filename='app.py'):
    """
    Returns a simple Flask template.
    """
    with open(filename, 'w') as f:
        f.write(
            """from flask import Flask
app = Flask(__name__)

@app.route('/')
def index():
    return 'Index Page'

@app.route('/hello')
def hello():
    return 'Hello, World'"""
            )
