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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 service_account_path(cls, project, service_account):
 """Return a fully-qualified service_account string."""

        return google.api_core.path_template.expand(
            "projects/{project}/serviceAccounts/{service_account}",
            project=project,
            service_account=service_account,
        )