Helper to verify that an object is a list (but not a data.frame) and that all its elements have non-empty names.
Examples
if (FALSE) { # \dontrun{
# Valid named list
is_named_list(list(a = 1, b = 2)) # TRUE
# Invalid: contains unnamed elements
is_named_list(list(a = 1, 2)) # FALSE
# Invalid: data.frame (technically a list, but we want a record/dict)
is_named_list(data.frame(a = 1)) # FALSE
} # }