code: def intcomma(value):
      
      orig = str(value)
      new = re.sub("^(-?\d+)(\d{3})", '\g<1>,\g<2>', orig)
      if orig == new:
          return new
      else:
          return intcomma(new)
docs: Borrowed from django.contrib.humanize
      
      Converts an integer to a string containing commas every three digits.
      For example, 3000 becomes '3,000' and 45000 becomes '45,000'.