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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 Conference(self, Id=0):
 """Queries a call conference object. :Parameters: Id : int Conference Id. :return: A conference object. :rtype: `Conference` """

        o = Conference(self, Id)
        if Id <= 0 or not o.Calls:
            raise SkypeError(0, 'Unknown conference')
        return o