     "mimetype": "text/x-python",
     "name": "python",
     "nbconvert_exporter": "python",
     "pygments_lexer": "ipython3",
     "version": "3.5.0"
    }
   },
   "nbformat": 4,
   "nbformat_minor": 0
  }
 
</s>
   "version": "3.7.2"
     "mimetype": "text/x-python",
     "name": "python",
     "nbconvert_exporter": "python",
     "pygments_lexer": "ipython3",
   "version": "3.7.2"
    }
   },
   "nbformat": 4,
   "nbformat_minor": 0
  }
keep keep keep keep replace keep keep keep keep keep
 #273: Remove nose dependency for graphs_trees/ (#277)
graphs_trees/tree_height/height_challenge.ipynb