The "arange" function in pylab (which you would have to load at the top) makes a list of numbers from 0 to 0.05 in increments of 0.001. So, x and y are just two lists. The line with the mesh grid ...

Data Visualization - Plotly and Cufflinks. Plotly is a library that allows you to create interactive plots that you can use in dashboards or websites (you can save them as html files or static images) ...