def process_fields_param(fields):
    """ Process 'fields' ES param.

    * Fields list is split if needed
    * '_type' field is added, if not present, so the actual value is
      displayed instead of 'None'
    """
    if not fields:
        return fields
    if isinstance(fields, six.string_types):
        fields = split_strip(fields)
    if '_type' not in fields:
        fields.append('_type')
    return {
        '_source_include': fields,
        '_source': True,
    }
Process 'fields' ES param.

    * Fields list is split if needed
    * '_type' field is added, if not present, so the actual value is
      displayed instead of 'None'