This object provides methods to manage code (as character vectors) in all
chunks in knitr source documents. For example,
knitr::knit_code$get() returns a named list of all code chunks (the
names are chunk labels), and knitr::knit_code$get('foo') returns the
character vector of the code in the chunk with the label foo.
knit_codeAn object of class list of length 6.