Flask NameError: name 'app' is not defined
<p>I am new in python and use learn flask framework, I got error in some line of code</p>

<p>please guide me:</p>

<pre><code>from flask import redirect
@app.route('/')
def index():
   return redirect("http://www.google.com")
</code></pre>

<p>Error: </p>

<pre><code>Traceback (most recent call last):
  File "redirect.py", line 2, in &lt;module&gt;
    @app.route('/')
NameError: name 'app' is not defined
</code></pre>

<p>Thanks in advance</p>