docstr: Initialize the data source for the FlairSampler.
  
  Args:
      data_source: dataset to sample from.
docstr_tok: ["Initialize","the","data","source","for","the","FlairSampler",".","Args",":","data_source",":","dataset","to","sample","from","."]
code: def set_dataset(self, data_source):
      """Initialize the data source for the FlairSampler.
  
      Args:
          data_source: dataset to sample from.
      """
      self.data_source = data_source
      self.num_samples = len(self.data_source)
  
imports: import logging
  import random
  from collections import defaultdict
  from typing import Dict
  import torch
  from torch.utils.data.sampler import Sampler
label_desc: Use image node_id 1 for calling the FlairSampler obj's underlying member method code with example usage: obj.set_dataset(data_source) without return types