new_contents: def _IsColor(color):
    """Try to determine if color is a hex color string.  
    Labels that look like hex colors will match too, unfortunately."""
    if not isinstance(color, basestring):
      return False
    color = color.strip('#')
    if len(color) != 3 and len(color) != 6:
      return False
    hex_letters = '0123456789abcdefABCDEF'
    for letter in color:
      if letter not in hex_letters:
        return False
    return True
  
subject: add util.py, missing from r53