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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 Greeting(self, Username=''):
 """Queries the greeting used as voicemail. :Parameters: Username : str Skypename of the user. :return: A voicemail object. :rtype: `Voicemail` """

        for v in self.Voicemails:
            if Username and v.PartnerHandle != Username:
                continue
            if v.Type in (vmtDefaultGreeting, vmtCustomGreeting):
                return v