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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_accessibility(self, plugin_override=True):
 """ Return the AccessibleTime object associated with the accessibility of this course """

        vals = self._hook_manager.call_hook('course_accessibility', course=self, default=self._accessible)
        return vals[0] if len(vals) and plugin_override else self._accessible