The macro actually creates a new text expansion macro for every line you supply in the variable Expansions; so if you have 600 lines in there it would create 600 separate macros. It places each of those in a macro group called Text Expansion. You'd know this already if you'd tried running Peter's macro.
Here's my version that allows you to specify the name of each text expansion macro that is created. Be sure to read the comment and edit the two red-coloured variables according to your needs.
Create Text Expansions.kmmacros (8.4 KB)
Many thanks to @peternlewis