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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 update_existing(self, *args, **kwargs):
 """ Update already existing properties of this CIM instance. Existing properties will be updated, and new properties will be ignored without further notice. Parameters: *args (list):
 Properties for updating the properties of the instance, specified as positional arguments. Each positional argument must be a tuple (key, value), where key and value are described for setting the :attr:`~pywbem.CIMInstance.properties` property. **kwargs (dict):
 Properties for updating the properties of the instance, specified as keyword arguments. The name and value of the keyword arguments are described as key and value for setting the :attr:`~pywbem.CIMInstance.properties` property. """


        for mapping in args:
            if hasattr(mapping, 'items'):
                for key, value in mapping.items():
                    try:
                        prop = self.properties[key]
                    except KeyError:
                        continue
                    prop.value = value
            else:
                for (key, value) in mapping:
                    try:
                        prop = self.properties[key]
                    except KeyError:
                        continue
                    prop.value = value
        for key, value in kwargs.items():
            try:
                prop = self.properties[key]
            except KeyError:
                continue
            prop.value = value