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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 _param_updated(self, pk):
 """Callback with data for an updated parameter"""

        if self._useV2:
            var_id = struct.unpack('<H', pk.data[:2])[0]
        else:
            var_id = pk.data[0]
        element = self.toc.get_element_by_id(var_id)
        if element:
            if self._useV2:
                s = struct.unpack(element.pytype, pk.data[2:])[0]
            else:
                s = struct.unpack(element.pytype, pk.data[1:])[0]
            s = s.__str__()
            complete_name = '%s.%s' % (element.group, element.name)

            # Save the value for synchronous access
            if element.group not in self.values:
                self.values[element.group] = {}
            self.values[element.group][element.name] = s

            logger.debug('Updated parameter [%s]' % complete_name)
            if complete_name in self.param_update_callbacks:
                self.param_update_callbacks[complete_name].call(
                    complete_name, s)
            if element.group in self.group_update_callbacks:
                self.group_update_callbacks[element.group].call(
                    complete_name, s)
            self.all_update_callback.call(complete_name, s)

            # Once all the parameters are updated call the
            # callback for "everything updated" (after all the param
            # updated callbacks)
            if self._check_if_all_updated() and not self.is_updated:
                self.is_updated = True
                self.all_updated.call()
        else:
            logger.debug('Variable id [%d] not found in TOC', var_id)