Easiest thing to do is to look at the code itself.
In JupyterNotebook you can quickly see arguments by hitting shift tab inside the parentheses for a function. Hit it again for even more info.
function? and function?? also work (or the function help if not in Jupyter).
Most of the code from the course consists of wrappers around Keras, so looking at the code + reading Keras documentation is probably the best way to go. People have discussed specific issues about the course codebase in this forum as well.