Return a string describing the probable encoding of a file.

def description_of(file, name='stdin'):
    """Return a string describing the probable encoding of a file."""
    u = UniversalDetector()
    for line in file:
        u.feed(line)
    u.close()
    result = u.result
    if result['encoding']:
        return '%s: %s with confidence %s' % (name,
                                              result['encoding'],
                                              result['confidence'])
    else:
        return '%s: no result' % name