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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_relationship_panels(self):

 """
 Add edit handler that includes "related" panels to applicable
 model classes that don't explicitly define their own edit handler.
 """

        from wagtailplus.utils.edit_handlers import add_panel_to_edit_handler
        from wagtailplus.wagtailrelations.edit_handlers import RelatedPanel

        for model in self.applicable_models:
            add_panel_to_edit_handler(model, RelatedPanel, _(u'Related'))