import math


def integral_default_gaussian(y, x):
    """Calculate the value of the integral from x to y of the erf function

    Parameters
    ----------
    y : float
        upper limit
    x : float
        lower limit

    Returns
    -------
    float
        Calculated value of integral

    """
    return 0.5 * (math.erf(x) - math.erf(y))