 
         # remap nested data according to rails conventions
         else if _.isObject(value)
-          value = self._collectNonEmptyFields(value)
-
           object["#{key}_attributes"] = value
           delete object[key]
 

    # builds body data. if $subject is an array of objects a nested data object is created
    # containing each object's data, referenced by object id
    data: ->
      subject = _.cloneDeep(@$subject)
      return subject if @$options['raw'] # do not modify data according to rails conventions

      if _.isArray(subject)

          # skip
        else if _.isArray(v)
          if _.isPlainObject(v[0])
            subset = _.map v, (x) -> self._cleanup(x)
            newObject[k] = _.reject subset, (x) -> _.isEmpty(x)

          else
            newObject[k] = v

        else if _.isPlainObject(v)
          obj = self._cleanup(v)
          newObject[k] = obj unless _.isEmpty(obj)

        else
