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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 add(self, tag, ref):
 """Add to the vgroup an object identified by its tag and reference number. Args:: tag tag of the object to add ref reference number of the object to add Returns:: total number of objects in the vgroup after the addition C library equivalent : Vaddtagref """


        n = _C.Vaddtagref(self._id, tag, ref)
        _checkErr('addtagref', n, 'invalid arguments')
        return n