I have a Python XML XPath expression ancestor-or-self::*[@foo]/@foo, and I need to modify it to get attribute @foo if it exists otherwise get attribute @bar.
I've tried to use or operator similar to condition like [@foo or @bar], but got an expression error.
XPath 1.0
For a correct XPath_Prefix, this XPath,

XPath_Prefix/@*[name()='foo' or name()='bar'][1]

will select the foo attribute if available; otherwise, the bar attribute.
XPath get one attribute or another?