Fits gaussians to delta t for each PMT pair.

    Parameters
    ----------
    data: 2d np.array: x = PMT combinations (465), y = time, entry = frequency
    time_s: length of data taking in seconds

    Returns
    -------
    numpy arrays with rates and means for all PMT combinations

def fit_delta_ts(data, time_s):
    """Fits gaussians to delta t for each PMT pair.

    Parameters
    ----------
    data: 2d np.array: x = PMT combinations (465), y = time, entry = frequency
    time_s: length of data taking in seconds

    Returns
    -------
    numpy arrays with rates and means for all PMT combinations
    """

    data = data / time_s

    xs = np.arange(-20, 21)

    def gaussian(x, mean, sigma, rate, offset):
        return rate / np.sqrt(2 * np.pi) /  \
            sigma * np.exp(-(x - mean)**2 / sigma**2) + offset

    rates = []
    means = []
    for combination in data:
        try:
            popt, _ = optimize.curve_fit(
                gaussian, xs, combination, p0=[0, 2, 1000, 20]
            )
        except RuntimeError:
            popt = (0, 0, 0, 0)
        rates.append(popt[2])
        means.append(popt[0])
    return np.array(rates), np.array(means)