     @_ensureType('contains')
     @_validateAttribute()
     throw new TypeError('contains must be a string') unless typeof @value is 'string'
-
-  toString: ->
-    return "#{@attribute} contains '#{@value}'"
 
   valueOf: ->
     filter = super


    @_ensureType('or')

  toString: ->
    if @filters.length > 1
      return "(#{@filters.join(') or (')})"
    else
      return String(@filters[0])

  valueOf: ->
    filter = super
    filter.filters = @filters.map(getValueOf)


    throw new Error('invalid range') if isNaN(@range[0]) or isNaN(@range[1])

  valueOf: ->
    filter = super
    filter.attribute = @attribute
