Hints

General

To extract multiple arguments in the function parameters so can you pack them with the *args operator for list or tuples or **kwargs for keyword-based arguments.
To pack or unpack use the * or ** operator.

1. Create a list of all wagons

Multiple arguments in the function parameters can be packed with the *args operator.

2. Fix list of wagons

Using unpacking with the * operator, lets you extract the first two elements of a list while keeping the rest intact.
To add another list into an existing list, you can use the * operator to "spread" the list.

3. Add missing stops

Using **kwargs as a function parameter will allow an arbitrary amount of keyword arguments to be passed.
Using **<dict> as an argument will unpack a dictionary into keyword arguments.
You can put keyword arguments in a {} or dict().
To get the values out of a dictionary, you can use the <dict>.values() method.

4. Extend routing information

Using **<dict> as an argument will unpack a dictionary into keyword arguments.
You can put keyword arguments in a {} or dict().

5. Fix the wagon depot

zip(*iterators) can use used to transpose a nested list.
To extract data from zipped iterators, you can use a for loop.
you can also unpack zipped iterators using *.
[*content] = zip(iterator_1, iterator_2) will unzip the tuple produced by zip() into a list.