With the help of The Library of Babel, we don't have to include the code block get-named-text into every Org file. I put the block into an Org file under my .emacs.d directory, $HOME/.emacs.d/src/resources/org-babel-lib.org . Then put this line into my .emacs:

( org-babel-lob-ingest ( expand-file-name "~/.emacs.d/src/resources/org-babel-lib.org" ) )