Not the parent, but i return heterogeneous lists of the same length to the excel to be used by xlwings. The first row being the headers, but every row below is obviously heterogeneous
"return key, value" is implicit. While "return [key, value]" is explicitly telling the full return-value. And it's (for me) more readable than "return (key, value)".
I don't see how "return (key, value)" is less readable than it's list counterpart. Now, why using a list that can grow, and so takes more space and maybe less efficient, for something that should not?
"return (key, value)" can be read as a function-call. Especially as space after the function-name is allowed in python. And performance on that level is no serious topic in python anyway. But this is mainly just a personal preference.
A list and tuple are not the same thing. There could be reasons to require a list explicitly but I couldn't really think of any obvious ones which is why I asked.