:sig
function runtime_safe_key(key : string, label : string = "runtime key") string

:params
key : runtime key
label : name for an empty-key error

:returns
A stable SHA-1 key.

:content
The function trims `key`. It reports an error for an empty key.

:example capy render
print(runtime_safe_key("docs task"), "\n")

:see-group
crypto
