def trim(x, y, low, high):
    """
    Mask two arrays applying bounds to the first array.

    Parameters
    ----------
    x : array
        independent variable
    y : array
        dependent variable
    low : float
        low bound
    high : float
        high bound

    Returns
    -------
    array :
        x with new range
    array :
        y with new range
    """
    mask = (x >= low) & (x <= high)
    return x[mask], y[mask]