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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 addValue(self, type_uri, value):
 """Add a single value for the given attribute type to the message. If there are already values specified for this type, this value will be sent in addition to the values already specified. @param type_uri: The URI for the attribute @param value: The value to add to the response to the relying party for this attribute @type value: unicode @returns: None """

        try:
            values = self.data[type_uri]
        except KeyError:
            values = self.data[type_uri] = []

        values.append(value)