title: flask-restplus nested namespace with blueprint and namespace
body: <p>I made api server with <code>flask-restplus</code>.</p>
  
  <p>While working with it, I noticed that it maybe have to versioning for scaling up.</p>
  
  <p>So refer the docs, I found Namespace and Blueprint is usuable.</p>
  
  <p>First, file structure like this.</p>
  
  <pre><code>/app
    - /main
      - __init__.py
      - /controller
        - /v1/
          - article_controller.py
    - __init__.py
  </code></pre>
  
  <p>[/main/v1/__init__.py]</p>
  
  <pre><code>from flask_restplus import Namespace, Api
  from flask import Blueprint
  
  from .article_controller import api as article_ns
  
  
  blueprint = Blueprint('api', __name__)
  
  api = Api(blueprint,
            title='Appeal API',
            version='1.0',
            description='Appeal API',
            )
  
  api.add_namespace(article_ns, path='/articles')
  </code></pre>
  
  <p>I import <code>article_controller.py</code> and add it via <code>add_namespace()</code>.</p>
  
  <p>[/main/__init__.py]</p>
  
  <pre><code>from flask_restplus import Api
  from flask import Blueprint
  
  from app.main.controller.v1 import api as api_v1
  
  
  blueprint = Blueprint('api', __name__)
  
  api = Api(blueprint,
            title='Appeal API v1',
            version='1.0',
            description='Appeal API v1',
            #   prefix='/api'
            )
  
  # Version1
  api.add_namespace(api_v1, path='/v1/')
  </code></pre>
  
  <p>Import <code>v1</code> and add it to namespace.</p>
  
  <p>But when I access to <code>/v1/articles</code>, Not found errors has occured.</p>
  
  <p>I can't catch where is the wrong code.</p>
  
  <p>Any solution here?</p>
  
  <p>Thanks.</p>