flask-wtf forms SelectMultipleField not allowing multiple selection

This is the Category.py to create fields

class CategoryForms(FlaskForm):
   cat_choices = [('sport', 'sport'),('music',music')]
   categories = SelectedMultipleField('Categories' choices = cat_choices)
   submit=SubmitField('Lets Go!')

This is the Category.html that displays the fields

<form action ='' method='Post'>
    {{form.hidden_tag}}
    <p>
         {{form.categories.label}}
         {{form.categories)row=3 multiple=True}
    </p>
    <p>
         {{form.submit()}}
    </p>
<form>

The routes.py

@app('category, methods['GET','POST'])
def category():
    form = CategoryForms()
    if request.method =='POST':
        if form.is_submitted():
           result = form.categories.data
           return render_template('cat-request.html', result=result)
     return render_template('category.html', title='Category', form = form)

My issue are:

1) The select options only allow for one section and not multiple. 2) When getting the user input, I did a for loop but nothing displays. Is this the right approach? Like below:

in the cat-request.html file

{% for value in result %}
    {{value}}
{% endfor %}