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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 provider_image(self):
 """Image path getter. This method uses a pluggable image provider to retrieve an image's path. """

        if self._image is None:
            if isinstance(self.configuration['disk']['image'], dict):
                ProviderClass = lookup_provider_class(
                    self.configuration['disk']['image']['provider'])
                self._image = ProviderClass(
                    self.configuration['disk']['image']).image
            else:
                # If image is not a dictionary, return it as is for backwards
                # compatibility
                self._image = self.configuration['disk']['image']
        return self._image