class_docstr: Build NN graph
code: def __init__(self, radius, n_neighbor):
      super(FixedRadiusNNGraph, self).__init__()
      self.radius = radius
      self.n_neighbor = n_neighbor
      self.frnn = FixedRadiusNearNeighbors(radius, n_neighbor)
  
imports: import dgl
  import torch
  import torch.nn
  import torch.nn.functional
  from torch.autograd import Function
  from torch.nn import Parameter
  from torch.nn.modules.utils import _single
label_desc: Use image node_id 1 to create a new FixedRadiusNNGraph object from inherited base classes: nn with example: obj = FixedRadiusNNGraph(radius, n_neighbor)