code: def get_symbol_idx(self, s):
      if s not in self.symbol2idx:
          return self.get_symbol_idx(self.unk_token)
      else:
          return self.symbol2idx[s]
  
imports: from operator import itemgetter
  import numpy
label_desc: Use image node_id 3 for calling the Vocab obj's underlying member method code with example usage: obj.get_symbol_idx(s) and returns: self, self