title: pip install package via proxy
body: <p>I tried to pip install using proxy, the proxy setting is correct because it works for npm install . what i tried is as below shown but got error message. any idea will be more than welcome!</p>
  
  <pre><code>set http_proxy=http://&lt;username&gt;:&lt;password&gt;@&lt;proxy_server&gt;:&lt;port&gt;
  
  set https_proxy=https://&lt;username&gt;:&lt;password&gt;@&lt;proxy_server&gt;:&lt;port&gt;
  
  pip install Flask
  
  Collecting Flask
    Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 407 Proxy Authentication Required'))': /simple/flask/
    Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 407 Proxy Authentication Required'))': /simple/flask/
    Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 407 Proxy Authentication Required'))': /simple/flask/
    Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 407 Proxy Authentication Required'))': /simple/flask/
    Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 407 Proxy Authentication Required'))': /simple/flask/
    Could not find a version that satisfies the requirement Flask (from versions: )
  No matching distribution found for Flask
  </code></pre>