code: def keep_only_digits(s):
      r'''
      local helper to just keep digits
      '''
      fs = ''
      for c in s:
          if c.isdigit():
              fs += c
  
      return int(fsf keep_only_digits(s):
      r'''
      local helper to just keep digits
      '''
      fs = ''
      for c in s:
          if c.isdigit():
              fs += c
  
      return int(fs)
docs: r'''
      local helper to just keep digits