how to export vector variables and other data structures into R as variables?

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All the examples I kind find here and in the documentation pass data from sage to R to be used once. I'd like to pass data that's in a sage (python) variable and turn it into an R variable that I can subsequntly use in %r codeblocks.

simple stuff like r.set('x', [1,2,3]) doesn't work because set expects a string. I could turn vectors into strings before passing them to set, but that's kind of klugy (and could be a pain for more complicated things.