Get block caching

[stolpa4]

Hello, it seems to me that caching get_block function can get broken, because in some cases this function may return None (e.g. when the block is not found, like here:

py-substrate-interface/substrateinterface/base.py

Lines 2223 to 2226 in eb9e75f

	try:
	self.init_runtime(block_hash=block_hash)
	except BlockNotFound:
	return None

). So once you have not found the block, there's no way to retry, as this None value is cached. We should do something with it.

[arjanz]

You mean when the node is not in sync yet or after a reorg? That is indeed undesirable, what I will try first is to never cache when None is returned. If that still doesn't work I will disable cache all together, as it does then more harm than good

[arjanz]

Caching is removed in latest release