          This is the list you would follow if applying the migrations to
          a database.
          """
          if node not in self.nodes:
              raise ValueError("Node %r not a valid node" % (node, ))
          return self.dfs(node, lambda x: self.dependencies.get(x, set()))
  
      def backwards_plan(self, node):
          """
          Given a node, returns a list of which dependent nodes (dependencies)
 
</s> remove             raise ValueError("Node %r not a valid node" % (node, ))
 </s> add             raise NodeNotFoundError("Node %r not a valid node" % (node, ), node) </s> remove             raise KeyError(
                "Migration %s dependencies reference nonexistent parent node %r" % (migration, parent)
 </s> add             raise NodeNotFoundError(
                "Migration %s dependencies reference nonexistent parent node %r" % (migration, parent),
                parent </s> remove         with self.assertRaisesMessage(ValueError, message):
 </s> add         with self.assertRaisesMessage(NodeNotFoundError, message): </s> remove             raise KeyError(
                "Migration %s dependencies reference nonexistent child node %r" % (migration, child)
 </s> add             raise NodeNotFoundError(
                "Migration %s dependencies reference nonexistent child node %r" % (migration, child),
                child
            raise NodeNotFoundError("Node %r not a valid node" % (node, ), node)
          This is the list you would follow if applying the migrations to
          a database.
          """
          if node not in self.nodes:
            raise NodeNotFoundError("Node %r not a valid node" % (node, ), node)
          return self.dfs(node, lambda x: self.dependencies.get(x, set()))
  
      def backwards_plan(self, node):
          """
          Given a node, returns a list of which dependent nodes (dependencies)
keep keep keep keep replace keep keep keep keep keep
 Fixed #23556 -- Raised a more meaningful error message when migrations refer to an unavailable node 
django/db/migrations/graph.py