code: def __init__(self, k=10):  # negative sampling rate = 10
      self.k = k
  
imports: import dgl
  import numpy
  import torch
  import torch.nn
  import torch.nn.functional
  import tqdm
  from dgl.data.knowledge_graph import FB15k237Dataset
  from dgl.dataloading import GraphDataLoader
  from dgl.nn.pytorch import RelGraphConv
label_desc: Use image node_id 1 to create a new NegativeSampler object  with example: obj = NegativeSampler(k)