    async def send_transactions(self, account, calls, nonce=None, max_fee=0):
        if nonce is None:
            execution_info = await account.get_nonce().call()
            nonce, = execution_info.result

        build_calls = []
        for call in calls:
            build_call = list(call)
            build_call[0] = hex(build_call[0])
            build_calls.append(build_call)

        (call_array, calldata, sig_r, sig_s) = self.signer.sign_transaction(hex(account.contract_address), build_calls, nonce, max_fee)
        return await account.__execute__(call_array, calldata, nonce).invoke(signature=[sig_r, sig_s])
The software performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.