'Override prime symbol to use Bakoma'

def _get_glyph(self, fontname, font_class, sym, fontsize, math=True):

    if (sym == u'\\prime'):
        return self.bakoma._get_glyph(fontname, font_class, sym, fontsize, math)
    else:
        uniindex = get_unicode_index(sym)
        font = self._get_font(u'ex')
        if (font is not None):
            glyphindex = font.get_char_index(uniindex)
            if (glyphindex != 0):
                return super(DejaVuFonts, self)._get_glyph(u'ex', font_class, sym, fontsize, math)
        return super(DejaVuFonts, self)._get_glyph(fontname, font_class, sym, fontsize, math)
