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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 create(self):
 """Create a single instance of notebook."""

        # Point to chart repo.
        out = helm(
            "repo",
            "add",
            "jupyterhub",
            self.helm_repo
        )
        out = helm("repo", "update")

        # Get token to secure Jupyterhub
        secret_yaml = self.get_security_yaml()

        # Get Jupyterhub.
        out = helm(
            "upgrade",
            "--install",
            self.release,
            "jupyterhub/jupyterhub",
            namespace=self.namespace,
            version=self.version,
            input=secret_yaml
        )
        if out.returncode != 0:
            print(out.stderr)
        else:
            print(out.stdout)