Python dictionary ordering -- insertion order preserved since 3.7

Old Python code uses OrderedDict everywhere because dictionaries were unordered. In modern Python, regular dicts preserve insertion order but some developers do not know this.

Since Python 3.7, dict preserves insertion order as a language guarantee (was implementation detail in 3.6). Use regular dict instead of OrderedDict. OrderedDict is only needed when: (1) order-sensitive equality comparison is needed (OrderedDict considers order, dict does not). (2) move_to_end() or popitem(last=True/False) methods are needed.

CPython 3.6 changed dict implementation to a compact, ordered design. Python 3.7 made this a language specification guarantee, not just an implementation detail.