def METHOD_NAME(temperature=27, salinity=35, pressure=10, formula_source="Mackenzie"):
    """
    Calculate sound speed in [m/s].
    Parameters
    ----------
    temperature: num
        temperature [deg C]
    salinity: num
        salinity [PSU, part per thousand]
    pressure: num
        pressure [dbars]
    formula_source: str, {"Mackenzie", "AZFP"}
        Source of formula used to calculate sound speed.
        "Mackenzie" (default) uses the formula from Mackenzie 1981
        (see Notes below) as implemented in ``arlpy`` package.
        "AZFP" uses the formula supplied in the AZFP Matlab code.
    Returns
    -------
    Sound speed [m/s] for each input temperature value.
    Notes
    -----
    Mackenzie KV (1981) Nine‐term equation for sound speed in the oceans.
    The Journal of the Acoustical Society of America, 70(3), 807–812.
    https://doi.org/10.1121/1.386920
    The ranges of validity encompass the following:
    temperature −2 to 30 °C, salinity 30 to 40 ppt, and depth 0 to 8000 m.
    """
    if formula_source == "Mackenzie":
        ss = (
            1448.96
            + 4.591 * temperature
            - 5.304e-2 * temperature**2
            + 2.374e-4 * temperature**3
        )
        ss += 1.340 * (salinity - 35) + 1.630e-2 * pressure + 1.675e-7 * pressure**2
        ss += -1.025e-2 * temperature * (salinity - 35) - 7.139e-13 * temperature * pressure**3
    elif formula_source == "AZFP":
        z = temperature / 10
        ss = (
            1449.05
            + z * (45.7 + z * (-5.21 + 0.23 * z))
            + (1.333 + z * (-0.126 + z * 0.009)) * (salinity - 35.0)
            + (pressure / 1000) * (16.3 + 0.18 * (pressure / 1000))
        )
    else:
        ValueError("Unknown formula source")
    return ss