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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def str_args(args):
 """formats a list of function arguments prettily not as code (kwargs are tuples (argname, argvalue) """

    res = []
    for x in args:
        if isinstance(x, tuple) and len(x) == 2:
            key, value = x
            if value and str_arg(value):
                res += ["%s=%s" % (key, str_arg(value))]
        else:
            res += [str_arg(x)]
    return ', '.join(res)