Get the selected values from html file to app in flask

I have a application build in flask (sorry I have produced a piece of code below since I am not able to put entire code here).

I need to get whatever is selected from dropdown. Below is the code in template.html where there is a dropdown. I have a name attribute here

template.html

<select  name="comp_select" onchange="update_selected_option_value(value)" method="POST">
    {% for ticker in tickers %}<option value="{{ticker}}" SELECTED>{{ticker}}</option>{% endfor %}
</select>

`

Now i am trying retrieve selected value so I am using below code

`

@app.route('/', methods=['GET','POST'])
def dropdown():   
    company_name = request.form['comp_select']
    return render_template('template.html')

`

So basically i need to get selected value in company_name . But I am not able to get it. Can anyone help me what wrong I am doing?