  
      def flatten_data(self, data):
          """Given a data dictionary ``{<attr_name>: <value_list>}``, returns a flattened dictionary according to :meth:`FormParser.is_a_list`.
          """
          #TODO : document + test
          flatdata = dict()
          for attr_name, attr_value in data.items():
              if self.is_a_list(attr_name):
                  if isinstance(attr_value, list):
                      flatdata[attr_name] = attr_value
 
</s> remove         #TODO: document
 </s> add  </s> remove 
        if request.method == 'POST':
 </s> add         elif request.method == 'POST':
  
      def flatten_data(self, data):
          """Given a data dictionary ``{<attr_name>: <value_list>}``, returns a flattened dictionary according to :meth:`FormParser.is_a_list`.
          """

          flatdata = dict()
          for attr_name, attr_value in data.items():
              if self.is_a_list(attr_name):
                  if isinstance(attr_value, list):
                      flatdata[attr_name] = attr_value
keep keep keep keep replace keep keep keep keep keep
 FomrParser now implements a work around for empty values in a list 
djangorestframework/parsers.py