code: def within(self, lat, lon, radius):
  		'''Convenience method to apply a $loc/$within/$center filter. Radius is in meters.'''
  		return self.filter(filter_helpers.within_(lat, lon, radius)f within(self, lat, lon, radius):
  		'''Convenience method to apply a $loc/$within/$center filter. Radius is in meters.'''
  		return self.filter(filter_helpers.within_(lat, lon, radius))
docs: Convenience method to apply a $loc/$within/$center filter. Radius is in meters.