code: def children(self, node, relations=None):
          
          g = self.get_graph()
          if node in g:
              children = list(g.successors(node))
              if relations is None:
                  return children
              else:
                  rset = set(relations)
                  return [c for c in children if len(self.child_parent_relations(c, node, graph=g).intersection(rset)) > 0 ]
          else:
              return []
docs: Return all direct children of specified node.
  
          Wraps networkx by default.
  
          Arguments
          ---------
  
          node: string
  
             identifier for node in ontology
  
          relations: list of strings
  
             list of relation (object property) IDs used to filter