title: I need to find the shortest path (distance) between a source node and a target node. Given that certain nodes MUST be included
body: <p>I need to get from the <strong>blue</strong> circle to the <strong>red</strong> circle. The path must include the <strong>black</strong> circle, (<strong>even though</strong> it might not be optimal). </p>
  
  <p><a href="https://i.stack.imgur.com/92BaM.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/92BaM.jpg" alt="Children Trasportation by Bus"></a></p>
  
  <p>i have included distances from node to node. and by using the  'dijkstra_path' i get:
  <a href="https://i.stack.imgur.com/81gqs.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/81gqs.jpg" alt="enter image description here"></a></p>
  
  <p>which is correct.</p>
  
  <p>But... what can i do to make sure 'kountoumas' is included or even a list of other nodes.</p>
  
  <p>and then run the algorithm or another one.</p>
  
  <p>thank you</p>