is.enum_type.RdThis function checks class of passed object. If vector of classes contains
"enum_type", then checks if all necessary fields are not null, namely
type_name and values, and whether type_name is a singular
character vector. Next, checks if fields_names is a character vector or null.
Lastly, all values need to be unique and proper enum_value objects.
is.enum_type(object)
TRUE if the object passed all tests described above, FALSE otherwise.