title: how to install python packages for brew installed pythons
body: <p>I just finished installing the latest stable version of python via Homebrew.</p>
  
  <p>$ brew install python3</p>
  
  <p>Everything works fine. I would like to install packages, for example PyMongo. 
  I don't have pip.</p>
  
  <p>$ pip
  -bash: pip: command not found</p>
  
  <p>and there is no Homebrew formulae for it:</p>
  
  <p>$ brew install PyMongo</p>
  
  <p>brew install PyMongo
  Error: No available formula for pymongo
  Searching formulae...
  Searching taps...</p>
  
  <p>Any idea what's the best way to install PyMongo on OS X when Python was installed via Homebrew. Thank you!</p>