How to use the cantools.database function in cantools

def test_as_kcd_string(self):
        """Test the KCD dump functionality.

        """

        filename = os.path.join('tests', 'files', 'dump.kcd')
        db = cantools.database.load_file(filename)

        with open(filename, 'rb') as fin:
            self.assertEqual(db.as_kcd_string().encode('ascii'), fin.read())

def test_vehicle(self):
        filename = os.path.join('tests', 'files', 'vehicle.dbc')
        db = cantools.database.load_file(filename)
        self.assertEqual(len(db.nodes), 1)
        self.assertEqual(db.nodes[0].name, 'UnusedNode')
        self.assertEqual(len(db.messages), 217)
        self.assertEqual(db.messages[216].name, 'RT_SB_Gyro_Rates')
        self.assertEqual(db.messages[216].frame_id, 155872546)
        self.assertEqual(db.messages[216].senders, [])
        self.assertEqual(str(db.messages[0]),
                         "message('RT_SB_INS_Vel_Body_Axes', 0x9588322, True, 8, None)")
        self.assertEqual(repr(db.messages[0].signals[0]),
                         "signal('Validity_INS_Vel_Forwards', 0, 1, 'little_endian', "
                         "False, 1, 0, 0, 1, 'None', False, None, None, 'Valid when "
                         "bit is set, invalid when bit is clear.')")
        self.assertEqual(db.messages[0].signals[0].receivers, [])
        self.assertEqual(db.messages[0].cycle_time, None)
        self.assertEqual(db.messages[0].send_type, None)
        self.assertEqual(repr(db.nodes[0]), "node('UnusedNode', None)")

def test_database_signals_check_failure(self):
        signal = cantools.database.can.Signal('S',
                                              7,
                                              33,
                                              'big_endian')

        message = cantools.database.can.Message(37,
                                                'M',
                                                4,
                                                [signal],
                                                strict=False)

        with self.assertRaises(cantools.database.errors.Error) as cm:
            cantools.database.can.Database([message])

        self.assertEqual(str(cm.exception),
                         'The signal S does not fit in message M.')

def test_strict_load(self):
        filenames = [
            os.path.join('tests', 'files', 'bad_message_length.kcd'),
            os.path.join('tests', 'files', 'bad_message_length.dbc'),
            os.path.join('tests', 'files', 'bad_message_length.sym')
        ]

        for filename in filenames:
            # Strict true.
            with self.assertRaises(cantools.database.Error) as cm:
                cantools.database.load_file(filename, strict=True)

            self.assertEqual(str(cm.exception),
                             'The signal Signal1 does not fit in message Message1.')

            # Strict false.
            db = cantools.database.load_file(filename, strict=False)

            # Sanity checks.
            message_1 = db.get_message_by_frame_id(1)
            self.assertEqual(message_1.length, 1)
            self.assertEqual(message_1.signals[0].start, 8)
            self.assertEqual(message_1.signals[0].length, 1)

(
                'Message4',
                1.9,
                "Expected signal 'Signal1' value greater than or equal to 2 in "
                "message 'Message4', but got 1.9."
            ),
            (
                'Message4',
                8.1,
                "Expected signal 'Signal1' value less than or equal to 8 in "
                "message 'Message4', but got 8.1."
            )
        ]

        for message_name, signal_value, error_message in datas:
            with self.assertRaises(cantools.database.EncodeError) as cm:
                db.encode_message(message_name, {'Signal1': signal_value})

            self.assertEqual(str(cm.exception), error_message)

        # Values out of range, but range checks disabled.
        datas = [
            ('Message1', 0),
            ('Message1', 3)
        ]

        for message_name, signal_value in datas:
            db.encode_message(message_name,
                              {'Signal1': signal_value},
                              strict=False)

        # Missing value.

return

        if len(data) != message.length:
            self._discarded += 1
            return

        name = message.name

        if message.is_multiplexed():
            # Handle the case where a multiplexer index is used that isn't
            # specified in the DBC file (ie. outside of the range). In this
            # case, we just discard the message, like we do when the CAN
            # message ID or length doesn't match what's specified in the DBC.
            try:
                name = format_multiplexed_name(message, data, True)
            except database.DecodeError:
                self._discarded += 1
                return

        if self._single_line:
            formatted = format_message(message, data, True, True)
            self._formatted_messages[name] = [
                '{:12.3f} {}'.format(timestamp, formatted)
            ]
        else:
            formatted = format_message(message, data, True, False)
            lines = formatted.splitlines()
            formatted = ['{:12.3f}  {}'.format(timestamp, lines[1])]
            formatted += [14 * ' ' + line for line in lines[2:]]
            self._formatted_messages[name] = formatted

        if name not in self._filtered_sorted_message_names:

def _do_generate_c_source(args):
    dbase = database.load_file(args.infile,
                               encoding=args.encoding,
                               strict=not args.no_strict)

    if args.database_name is None:
        basename = os.path.basename(args.infile)
        database_name = os.path.splitext(basename)[0]
        database_name = camel_to_snake_case(database_name)
    else:
        database_name = args.database_name

    filename_h = database_name + '.h'
    filename_c = database_name + '.c'
    fuzzer_filename_c = database_name + '_fuzzer.c'
    fuzzer_filename_mk = database_name + '_fuzzer.mk'

    header, source, fuzzer_source, fuzzer_makefile = generate(