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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 directives(self):
 """Returns all directives applicable to this Hug API"""

        directive_sources = chain(hug.defaults.directives.items(), getattr(self, '_directives', {}).items())
        return {'hug_' + directive_name: directive for directive_name, directive in directive_sources}