TypeError: iterable argument required

[Νικόλαος Κούρας]

>>> mail = None
>>> mail = mail or 7
>>> mail
7

>>> mail = None
>>> mail = 7 or mail
>>> mail
7

Here no matter the order iam writing the comparison it always return
the number.

why not the same here?

>>> mail = None
>>> mail = mail or ''
>>> mail
''

>>> mail = None
>>> mail = '' or mail
>>> mail
>>>

Why the or operator behaves differently with numbers than from
strings?

Please explain to me how it parses it with words.

Thank you.