function _verifyCall(address logicVerifier) ... {
    (bool success, bytes memory returnedData) = logicVerifier.call(...);  // call EOA will succeed, but no data returned
    _validateCall(false, success, returnedData);   // will revert due to lack of data
    bytes4 magicValue = abi.decode(returnedData, (bytes4));
    if (bytes3(magicValue) != bytes3(ILSP20.lsp20VerifyCall.selector)) // otherwise it will revert here
            revert LSP20InvalidMagicValue(false, returnedData);
    ...
}
function isValidSignature(...) ... {
    address _owner = owner();
    // If owner is a contract
    if (_owner.code.length > 0) {
        (bool success, bytes memory result) = _owner.staticcall( ... );

    }
    // If owner is an EOA
    else {
        ...
    }
}
