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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 init_providers(self, provider, kwargs):
 """ Inits main and fallback provider if relevant :param provider: Provider name to use :param kwargs: Additional kwargs :raises ValueError: If provider name or fallback names are not valid providers, a :exc:`ValueError` will be raised """

        self.provider = notifiers.get_notifier(provider, strict=True)
        if kwargs.get("fallback"):
            self.fallback = notifiers.get_notifier(kwargs.pop("fallback"), strict=True)
            self.fallback_defaults = kwargs.pop("fallback_defaults", {})