def strip_byte_order_mark(cls, data):
        """If a byte-order mark is present, strip it and return the encoding it implies."""
        encoding = None
        if (len(data) >= 4) and (data[:2] == b'\xfe\xff') \
               and (data[2:4] != '\x00\x00'):
            encoding = 'utf-16be'
            data = data[2:]
        elif (len(data) >= 4) and (data[:2] == b'\xff\xfe') \
                 and (data[2:4] != '\x00\x00'):
            encoding = 'utf-16le'
            data = data[2:]
        elif data[:3] == b'\xef\xbb\xbf':
            encoding = 'utf-8'
            data = data[3:]
        elif data[:4] == b'\x00\x00\xfe\xff':
            encoding = 'utf-32be'
            data = data[4:]
        elif data[:4] == b'\xff\xfe\x00\x00':
            encoding = 'utf-32le'
            data = data[4:]
        return data, encoding
If a byte-order mark is present, strip it and return the encoding it implies.