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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _initialize_data(self):
 """ This method is called once on construction. After that, it may be manually called again to reset the device to its default state. After the first call during construction, the class is frozen. This means that attempting to define a new member variable will raise an exception. This is to prevent typos from inadvertently and silently adding new members instead of accessing existing ones. """

        self.serial_command_mode = False
        self.pump_overspeed = False

        self.start_commanded = False
        self.stop_commanded = False
        self.hold_commanded = False

        # Real device remembers values from last run, we use arbitrary defaults
        self.temperature_rate = 5.0  # Rate of change of temperature in C/min
        self.temperature_limit = 0.0  # Target temperature in C

        self.pump_speed = 0  # Pump speed in arbitrary unit, ranging 0 to 30
        self.temperature = 24.0  # Current temperature in C

        self.pump_manual_mode = False
        self.manual_target_speed = 0