Use six.unichr()

from functools import update_wrapper

import six

import pybtex.io

from pybtex.bibtex import utils

from pybtex.bibtex.exceptions import BibTeXError

def int_to_chr(i):

    n = i.pop()

    try:

        char = unichr(n)

        char = six.unichr(n)

    except ValueError:

        raise BibTeXError('%i passed to int.to.chr$', n)

    i.push(char)

"""

Make a table of character widths to use with bibtex width$ function.

"""

from __future__ import print_function, unicode_literals

import six

def make_table(font_filename, output):

    import sys

    charcode, gindex = font_face.get_first_char()

    while gindex:

        font_face.load_glyph(gindex, FT_LOAD_NO_SCALE)

        yield unichr(charcode), font_face.glyph.metrics.horiAdvance

        yield six.unichr(charcode), font_face.glyph.metrics.horiAdvance

        charcode, gindex = font_face.get_next_char(charcode, gindex)