Compares the column classes of a data.frame with
is_col_classes(dat, classes, method = "identical")a data.frame or list
a list of column classes. Its names must match the names of dat exactly (see example)
if all, ensure that all columns named in classes are present in dat,
if any, ensure that any of the columns named in classes are present in dat,
if identical, ensure that the names of dat and classes are identical