docstr: helper deleting a letter from dictionary 
docstr_tok: ["helper","deleting","a","letter","from","dictionary"]
code: def __delete_if_zero_letters(self, letter):
      """helper deleting a letter from dictionary"""
      if self.__letters[letter] == 0:
          del self.__letters[letter]
  
file_path: coding-problems/Hashing DS/anagram_indices.py
label_desc: Use image node_id 3 for calling the LettersCounter obj's underlying member method code with example usage: obj.__delete_if_zero_letters(letter) without return types