Merge ElementBase into Element?

[janosh]

@shyuep Should we merge ElementBase into Element? It says ElementBase has no enum values so it can be subclassed but it isn't actually subclassed anywhere in pymatgen. Seems cleaner to only have an Element class.

pymatgen/pymatgen/core/periodic_table.py

Lines 30 to 33 in 3d4d160

	class ElementBase(Enum):
	"""Element class defined without any enum values so it can be subclassed."""
	def __init__(self, symbol: str):

[mkhorton]

Why was ElementBase created to start with, presumably for good reason? I vaguely remember this, can try and find the PR.

[janosh]

Here's the PR: #2005 by @jmmshn.

It also lists subclasses as the reason for creating ElementBase.

[mkhorton]

I see the mention for API use. Perhaps it was used to define a class for intercalant elements?

[jmmshn]

I think it was to get nested as_dict / from_dict to work properly. So the problem was that all the classes in emmet that had these classes required very custom construction and I wanted to have a a definition of these classes that behaved more like dataclasses so serialization was less troublesome. There were many times where the objects serialized only when they were top level.

[janosh]

@jmmshn Thanks for the context! I'll add this to the ElementBase doc str.