Return argument type bytes1 is not implicitly convertible to expected type (type of first return variable) bytes memory.

这个错误提示表明函数返回的类型是 bytes1，但是函数定义中第一个返回变量的类型是 bytes memory，这两个类型不兼容。需要修改函数定义或者返回值类型，使它们匹配。具体的修改方法需要根据具体的代码情况来确定。

相关问题

join() argument must be str or bytes, not 'list'

This error occurs when you try to use the `join()` method with a list as an argument. The `join()` method can only be used with strings or bytes, not with a list.

To fix this error, you need to convert the list to a string or byte object before using the `join()` method. For example:

my_list = ['a', 'b', 'c']
my_string = ''.join(my_list)
print(my_string)

Output:

'abc'

In this example, we first create a list `my_list` with three elements. We then convert the list to a string using the `join()` method and store the result in a variable `my_string`. Finally, we print the value of `my_string` which is `'abc'`.