new_contents: from __future__ import unicode_literals
  
  from rest_framework_gis.filters import InBBOXFilter, DistanceToPointFilter
  from coreapi.document import Field
  
  
  class GeotrekInBBoxFilter(InBBOXFilter):
      """
      Override DRF gis InBBOXFilter with coreapi field descriptors
      """
      def get_schema_fields(self, view):
          field_in_bbox = Field(name=self.bbox_param, required=False,
                                description='Filter elements contained in bbox',
                                example='XXX')
          field_dim = Field(name='dim', required=False,
                            description='Set geometry dimension (2 by default for 2D, 3 for 3D)',
                            example=3, type=int())
          return field_in_bbox, field_dim
  
  
  class GeotrekDistanceToPointFilter(DistanceToPointFilter):
      """
      Override DRF gis DistanceToPointFilter with coreapi field descriptors
      """
      def get_schema_fields(self, view):
          field_dist = Field(name=self.dist_param, required=False,
                             description='Distance max between point and elements',
                             example='XXX')
          field_point = Field(name=self.point_param, required=False,
                              description='Reference point to compute distance',
                              example='YES MAN', )
          return field_dist, field_point
subject: add filters with description