code: def hex_to_unichr(hex_string):
      
      if (hex_string is None) or (len(hex_string) < 1):
          return None
      if hex_string.startswith("U+"):
          hex_string = hex_string[2:]
      return int_to_unichr(int(hex_string, base=16))
docs: Return the Unicode character with the given codepoint,
      given as an hexadecimal string.
  
      Return ``None`` if ``hex_string`` is ``None`` or is empty.
  
      Example::
          "0061"   => a
          "U+0061" => a
  
      :param str hex_string: the Unicode codepoint of the desired character
      :rtype: (Unicode) str