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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_provider(self, provider_name='default'):
 """Fetch provider with the name specified in Configuration file"""

        try:
            if self._providers is None:
                self._providers = self._initialize_providers()
            return self._providers[provider_name]
        except KeyError:
            raise AssertionError(f'No Provider registered with name {provider_name}')