keywords in python

It turns out that class is one of Python’s keywords. The interpreter uses keywords to recognize the structure of the program, and they cannot be used as variable names.

    False class finally is return
    None continue for lambda try
    True def from nonlocal while
    and del global not with
    as elif if or yield
    assert else import pass  
    break except in raise  

    You might want to keep this list handy. If the interpreter complains about one of your variable names and you don’t know why, see if it is on this list.