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With *(23,), you are unpacking the values in the tuple (23,) as positional arguments, following the positional arguments that are already defined, namely 3 for a and 7 for b, so 23 would be assigned to parameter c, which is why fun(3, 7, d=10, *(23,)) works, but in fun(3, 7, c=10, *(23,)) you are also assigning to value 10 to c as a keyword argument, so it is considered a conflict as c cannot be assigned with both 23 and 10.

Note that while legal, it is discouraged by some to unpack iterable arguments after keyword arguments, as discussed here, although the syntax is ultimately ruled to stay.

Inside NonMeta.__new__, x is an instance of NonMeta, so the assignment to x.attr is creating an instance attribute for the instance x.

Inside Meta.__new__, x is an instance of Meta, namely a new class. In this case, x is the class WithMeta, so the assignment to x.attr creates a class attribute.

The class statement is, in some sense, syntactic sugar for a call to the metatype. That is,

Perhaps try:

Use r before the string to specify it is a raw string.

Your variable name is incorrect. It should be rannum-inputUser and not rannum-input.

Your code works fine on my ubuntu. (minus the typo at the end)

The error mean that you never used a variable named "directory" before trying to put it in _path, i.e. you never went in the if (which is weird since you should at least hit the root at some point)

You don't need a main function in test1 file. Just have the Class C in there.

test1.py