import math


def xyGaussian(x, y, a, bx, by, sigmax, sigmay):
    """ 
        # Two dimensional gaussian function.
        # from https://en.wikipedia.org/wiki/Gaussian_function
        >>> xyGaussian(0, 0, 1, 0, 0, 10, 10)
        1.0
        >>> xyGaussian(0, 0, 1, 1000, 0, 10, 10)
        0.0
    """
    return a * math.exp(-((x-bx)**2/(2*sigmax**2)+(y-by)**2/(2*sigmay**2)))