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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 get(cls, dname):
 """ Get the requested domain @param dname: Domain name @type dname: str @rtype: Domain or None """

        Domain = cls
        dname = dname.hostname if hasattr(dname, 'hostname') else dname.lower()
        return Session.query(Domain).filter(Domain.name == dname).first()