Python-将2D高斯拟合到数据集

I have data points in a .txt file (delimiter = white space), the first column is x axis and the second is the y axis. I want to fit a 2D Gaussian to theses data points using Python. Truth is, I don't understand the theory behind Gaussian fitting (either one or two dimensional). I have read similar posts here on stackoverflow and got a code, but it's not fitting well. Please someone help. Thanks file (delimiter =