title: How to only keep nodes in networkx-graph with 2+ outgoing edges or 0 outgoing edges?
body: <p>I have Directed Graph in networkx. I want to only keep those nodes which have two or more than two outgoing edges or no outgoing edge at all. How do I do this?</p>
  
  <p>or </p>
  
  <p>How do I removes nodes which have exactly one outgoing edge in a networkx graph.</p>