Your code hasn't actually created an object named data, so R is falling back to the function data() (used for loading built-in datasets). A function is called a "closure" by R.
Were you maybe adapting this code from an example somewhere? I'm not quite sure what you're doing here and I can't run your code (it's not reproducible as-is, since it relies on files local to your system), but I suspect you need to have the name of your data frame pitcher in the place of data.
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