code: def _sortValue_isMonospace(font):
      
      if font.info.postscriptIsFixedPitch:
          return 0
      if not len(font):
          return 1
      testWidth = None
      for glyph in font:
          if testWidth is None:
              testWidth = glyph.width
          else:
              if testWidth != glyph.width:
                  return 1
      return 0
docs: Returns 0 if the font is monospace.
      Returns 1 if the font is not monospace.