how to obtain the length of list of address?

[QuetzalAzul]

Im trying to compile this code

def balanceOfBatch(accounts: address[50], ids: uint256[50]) -> uint256[100]:
assert len(accounts) == len(ids), "ERC1155: accounts and ids length mismatch"

but tells me that len only function for bytes and string types

[fubuloubu]

I made an issue for this, but honestlly you don't need to do that check. Both arrays are "static arrays" meaning they cannot be less than 50 in length, so the length check is kind of unnecessary.

Still, it should be a thing you can do: #2347