user=> (doc first)
-------------------------
clojure.core/first
([coll])
  Returns the first item in the collection. Calls seq on its
    argument. If coll is nil, returns nil.
nil

user=> (doc rest)
-------------------------
clojure.core/rest
([coll])
  Returns a possibly empty seq of the items after the first. Calls seq on its
  argument.
nil

user=> (doc first)
-------------------------
clojure.core/first
([coll])
  Returns the first item in the collection. Calls seq on its
    argument. If coll is nil, returns nil.
nil
user=> (doc rest)
-------------------------
clojure.core/rest
([coll])
  Returns a possibly empty seq of the items after the first. Calls seq on its
  argument.
nil