code: def __word2art(word, font, chr_ignore, letters):
      
      split_list = []
      result_list = []
      splitter = "\n"
      for i in word:
          if (ord(i) == 9) or (ord(i) == 32 and font == "block"):
              continue
          if (i not in letters.keys()):
              if (chr_ignore):
                  continue
              else:
                  raise artError(str(i) + " is invalid.")
          if len(letters[i]) == 0:
              continue
          split_list.append(letters[i].split("\n"))
      if font in ["mirror", "mirror_flip"]:
          split_list.reverse()
      if len(split_list) == 0:
          return ""
      for i in range(len(split_list[0])):
          temp = ""
          for j in range(len(split_list)):
              if j > 0 and (
                      i == 1 or i == len(
                          split_list[0]) -
                      2) and font == "block":
                  temp = temp + " "
              temp = temp + split_list[j][i]
          result_list.append(temp)
      if "win32" != sys.platform:
          splitter = "\r\n"
      result = (splitter).join(result_list)
      if result[-1] != "\n":
          result += splitter
      return result
docs: Return art word.
  
      :param word: input word
      :type word: str
      :param font: input font
      :type font: str
      :param chr_ignore: ignore not supported character
      :type chr_ignore: bool
      :param letters: font letters table
      :type letters: dict
      :return: ascii art as str