parameters: (self, counter, unknown_token, reserved_tokens, most_freq_count,
                              min_freq)
docstring: Indexes keys of `counter`.
  
  
          Indexes keys of `counter` according to frequency thresholds such as `most_freq_count` and
          `min_freq`.
docstring_summary: Indexes keys of `counter`.
docstring_tokens: Indexes keys of counter .
function: def _index_counter_keys(self, counter, unknown_token, reserved_tokens, most_freq_count,
                              min_freq):
          """Indexes keys of `counter`.
  
  
          Indexes keys of `counter` according to frequency thresholds such as `most_freq_count` and
          `min_freq`.
          """
  
          assert isinstance(counter, collections.Counter), \
              '`counter` must be an instance of collections.Counter.'
  
          unknown_and_reserved_tokens = set(reserved_tokens) if reserved_tokens is not None else set()
          unknown_and_reserved_tokens.add(unknown_token)
  
          token_freqs = sorted(counter.items(), key=lambda x: x[0])
          token_freqs.sort(key=lambda x: x[1], reverse=True)
  
          token_cap = len(unknown_and_reserved_tokens) + (
              len(counter) if most_freq_count is None else most_freq_count)
  
          for token, freq in token_freqs:
              if freq < min_freq or len(self._idx_to_token) == token_cap:
                  break
              if token not in unknown_and_reserved_tokens:
                  self._idx_to_token.append(token)
                  self._token_to_idx[token] = len(self._idx_to_token) - 1
function_tokens: def _index_counter_keys ( self , counter , unknown_token , reserved_tokens , most_freq_count , min_freq ) : assert isinstance ( counter , collections . Counter ) , '`counter` must be an instance of collections.Counter.' unknown_and_reserved_tokens = set ( reserved_tokens ) if reserved_tokens is not None else set ( ) unknown_and_reserved_tokens . add ( unknown_token ) token_freqs = sorted ( counter . items ( ) , key = lambda x : x [ 0 ] ) token_freqs . sort ( key = lambda x : x [ 1 ] , reverse = True ) token_cap = len ( unknown_and_reserved_tokens ) + ( len ( counter ) if most_freq_count is None else most_freq_count ) for token , freq in token_freqs : if freq < min_freq or len ( self . _idx_to_token ) == token_cap : break if token not in unknown_and_reserved_tokens : self . _idx_to_token . append ( token ) self . _token_to_idx [ token ] = len ( self . _idx_to_token ) - 1