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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 set(self, field, value):
 """ Sets the value of an app field. :param str field: The name of the app field. Trying to set immutable fields ``uuid`` or ``key`` will raise a ValueError. :param value: The new value of the app field. :raises: ValueError """

        if field == 'uuid':
            raise ValueError('uuid cannot be set')
        elif field == 'key':
            raise ValueError(
                'key cannot be set. Use \'reset_key\' method')
        else:
            self.data[field] = value