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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_field_value(self, field_name, value):
 """ Set value of response field named `field_name`. If response contains single item, its field is set. If response contains multiple items, all the items in response are edited. To edit response meta(e.g. 'count') edit response directly at `event.response`. :param field_name: Name of response field value of which should be set. :param value: Value to be set. """

        if self.response is None:
            return

        if 'data' in self.response:
            items = self.response['data']
        else:
            items = [self.response]

        for item in items:
            item[field_name] = value