Intercepts assignment by the pre-1.11.0 Title-Case column names
(e.g., df$Cohort <- v) and stops with a migration message. All
other assignment falls through to the data.frame method via
NextMethod().
Intercepts assignment by the pre-1.11.0 Title-Case column names
(e.g., df$Cohort <- v) and stops with a migration message. All
other assignment falls through to the data.frame method via
NextMethod().