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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_search_form(self):
 """ Returns search form instance. :rtype: django.forms.ModelForm. """

        #noinspection PyUnresolvedReferences
        if 'q' in self.request.GET:
            #noinspection PyUnresolvedReferences
            return self.search_form_class(self.request.GET)
        else:
            return self.search_form_class(placeholder=_(u'Search'))