Check that a character vector of levels are all valid levels.
Arguments
- level
character vector of levels. Valid levels are:
"MLB" for Major League Baseball
"AAA" for Triple-A
"AA" for Double-A
"A+" for High-A
"A" for Single-A
"SS" (defunct since 2020) for Short-Season A and Rookie Advanced
"CL" for Complex Leagues
"DSL" for Dominican Summer League
Value
simply returns the input vector level but throws error if invalid levels are present