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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_viewer_names(self, dataobj):
 """Returns a list of viewer names that are registered that can view `dataobj`. """

        res = []
        for bnch in self.viewer_db.values():
            for vtype in bnch.vtypes:
                if isinstance(dataobj, vtype):
                    res.append(bnch.vname)
        return res