Storing a list of items in an _environment.local file

[arnaudgallou]

Description

The title says it all. Is it possible to store a list of items in an _environment.local file? If so, how?
I've a bunch of related Google sheets I'd like to read in a document. Instead of creating a variable for each file, I was thinking of storing the sheet IDs in a list, for convenience.
E.g.:

GS_KEYS=[
 "key_1",
 "key_2",
 "key_n"
]

This is to be handled in R.

[mcanouil]

_environment is following usual environment variable specification.
It does not have complex structure (most of the time depending on the environment being Bash, PowerShell, etc.), so use whatever separator and split afterwards.