How can I pass optional or keyword parameters from one function to another?

Collect the arguments using the * and ** specifiers in the functions parameter list; this gives you the positional arguments as a tuple and the keyword arguments as a dictionary. You can then pass these arguments when calling another function by using * and **:

def f(x, *args, **kwargs):
    kwargs['width'] = '14.3c'
    g(x, *args, **kwargs)