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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 call_env_updated(cls, kb_app, sphinx_app: Sphinx, sphinx_env: BuildEnvironment):
 """ On the env-updated event, do callbacks """

        for callback in EventAction.get_callbacks(kb_app, SphinxEvent.EU):
            callback(kb_app, sphinx_app, sphinx_env)