Small fix

[marisaleung]

Changed variable to variable_name to make it clear that the parameter is a string and not a variableModel.

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This change is 

[googlebot]

So there's good news and bad news.

👍 The good news is that everyone that needs to sign a CLA (the pull request submitter and all commit authors) have done so. Everything is all good there.

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[googlebot]

CLAs look good, thanks!

[RoboErikG]

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Review status: 0 of 1 files reviewed at latest revision, all discussions resolved.

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