dx = pd.Index([1, 2, 3, 4])
        >>> idx.is_numeric()  # doctest: +SKIP
        True

        >>> idx = pd.Index([1, 2, 3, 4.0, np.nan])
        >>> idx.is_numeric()  # doctest: +SKIP
        True

        >>> idx = pd.Index([1, 2, 3, 4.0, np.nan, "Apple"])
        >>> idx.is_numeric()  # doctest: +SKIP
        False
        zQ.is_numeric is deprecated. Use pandas.api.types.is_any_real_numeric_dtype insteadr�