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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 list_metrics():
 """List metrics available."""

    for name, operator in ALL_OPERATORS.items():
        print(f"{name} operator:")
        if len(operator.cls.metrics) > 0:
            print(
                tabulate.tabulate(
                    headers=("Name", "Description", "Type"),
                    tabular_data=operator.cls.metrics,
                    tablefmt=DEFAULT_GRID_STYLE,
                )
            )