"Parse a variable ASSIGNMENT in a header argument.
If the right hand side of the assignment has a literal value
return that value, otherwise interpret as a reference to an
-external resource and find it's value using
+external resource and find its value using
`org-babel-ref-resolve'. Return a list with two elements. The
first element of the list will be the name of the variable, and
the second will be an emacs-lisp representation of the value of