code: def subset_font(font_in, font_out, unicodes, opts):
      font_out_raw = font_out
      if not font_out_raw.endswith(".ttf"):
          font_out_raw += ".ttf"
      subset_font_raw(font_in, font_out_raw, unicodes, opts)
      if font_out != font_out_raw:
          os.rename(font_out_raw, font_out)
  
file_path: matplotlib/tools/subset.py
imports: import getopt
  import os
  import struct
  import subprocess
  import sys
  import fontforge
label_desc: Use image node_id 4 for calling a global function with example usage: subset_font(font_in, font_out, unicodes, opts) without return types