A Solidity function, i.e., the address of a contract and the selector of a function within that contract.
The address of the contract. Must be a 40-character long hex string (excluding the "0x"-prefix).
The selector of the function. Must be an 8-character long hex string (excluding the "0x"-prefix).
A Solidity function, i.e., the address of a contract and the selector of a function within that contract.