     remove: (node) ->
         correct = node instanceof Abstract
         invalid "The supplied node is not valid"
-        abstract = "The supplied not is abstract"
+        abstract = "The supplied node is abstract"
         isEqual = (n) -> n.tag is node.tag
         throw new Error invalid unless correct
         throw new Error abstract if node.abstract()

    prepend: (node) ->
        correct = node instanceof Abstract
        invalid "The supplied node is not valid"
        abstract = "The supplied not is abstract"
        isEqual = (n) -> n.tag is node.tag
        throw new Error invalid unless correct
        throw new Error abstract if node.abstract()

    append: (node) ->
        correct = node instanceof Abstract
        invalid "The supplied node is not valid"
        abstract = "The supplied node is abstract"
        isEqual = (n) -> n.tag is node.tag
        throw new Error invalid unless correct
        throw new Error abstract if node.abstract()
