title: ImportError: No module named flask.ext.sqlalchemy in virtualenv
body: <p>Here is the main error I get when trying to run the following code in python3 from flask_sqlalchemy import SQLAlchemy</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/jsnyder10/.local/bin/flask", line 11, in &lt;module&gt;
  sys.exit(main())
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/flask/cli.py", line 513, in main
  cli.main(args=args, prog_name=name)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/flask/cli.py", line 380, in main
  return AppGroup.main(self, *args, **kwargs)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/click/core.py", line 697, in main
  rv = self.invoke(ctx)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/click/core.py", line 1066, in invoke
  return _process_result(sub_ctx.command.invoke(sub_ctx))
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/click/core.py", line 895, in invoke
  return ctx.invoke(self.callback, **ctx.params)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/click/core.py", line 535, in invoke
  return callback(*args, **kwargs)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/click/decorators.py", line 64, in new_func
  return ctx.invoke(f, obj, *args[1:], **kwargs)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/click/core.py", line 535, in invoke
  return callback(*args, **kwargs)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/flask/cli.py", line 423, in run_command
  app = DispatchingApp(info.load_app, use_eager_loading=eager_loading)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/flask/cli.py", line 152, in __init__
  self._load_unlocked()
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/flask/cli.py", line 176, in _load_unlocked
  self._app = rv = self.loader()
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/flask/cli.py", line 237, in load_app
  rv = locate_app(self.app_import_path)
    File "/home/jsnyder10/.local/lib/python3.5/site-packages/flask/cli.py", line 90, in locate_app
  __import__(module)
    File "/home/jsnyder10/Documents/CS50/pset7/pset7/finance/application.py", line 2, in &lt;module&gt;
  from flask_sqlalchemy import SQLAlchemy
  ImportError: No module named 'flask_sqlalchemy'
  </code></pre>
  
  <p>Not sure if it is related but when I update sqlaclhemy it gives the following pip heads up. I tried updating pip, but for some reason version 9.0.1 says it is upgraded but doesn't actually update.</p>
  
  <pre><code>You are using pip version 8.1.1, however version 9.0.1 is available.
  You should consider upgrading via the 'pip install --upgrade pip' command.
  </code></pre>
  
  <p>Here is what I get when I run pip list, as you can see both sqlalchemy and flask-sqlalchemy are installed.</p>
  
  <pre><code>DEPRECATION: The default format will switch to columns in the future. You can use --format=(legacy|columns) (or define a format=(legacy|columns) in your pip.conf under the [list] section) to disable this warning.
  appdirs (1.4.3)
  click (6.7)
  Flask (0.12.1)
  Flask-SQLAlchemy (2.2)
  itsdangerous (0.24)
  Jinja2 (2.9.6)
  MarkupSafe (1.0)
  packaging (16.8)
  pip (9.0.1)
  pyparsing (2.2.0)
  setuptools (35.0.2)
  six (1.10.0)
  SQLAlchemy (1.1.9)
  Werkzeug (0.12.1)
  wheel (0.29.0)
  </code></pre>
  
  <p>I'm guessing it was using the incorrect Python version. I never got to the bottom of this, but nuking my virtual machine and making a new one fixed it. Thanks for the help guys, wish I could have fixed it.</p>