character vector indicating the type of measurement for each
block. Values regular user can choose: "A", "B", "newA"
Values Expert user can choose: "A", "B", "newA", "PLScore", "PLScow".
The length of modes must be equal to the length of blocks.
blocks
list defining the blocks of manifest variables
Value
validated modes
Details
Internal function. check_modes is called by check_specs.