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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 provision(self, tool: Tool) -> docker.models.containers.Container: """ Provisions a mountable Docker container for a given tool. """

        if not self.is_installed(tool):
            raise Exception("tool is not installed: {}".format(tool.name))

        client = self.__installation.docker
        return client.containers.create(tool.image)