code: def fix_trim_curves(obj):
      
      # Validate input
      if obj.pdimension != 2:
          raise GeomdlException("Input geometry must be a surface")
  
      # Get trims of the surface
      for o in obj:
          trims = o.trims
          if not trims:
              continue
  
          # Get parameter space bounding box
          parbox = get_par_box(o.domain, True)
  
          # Check and update trim curves with respect to the underlying surface
          updated_trims = []
          for trim in trims:
              flag, trm = check_trim_curve(trim, parbox)
              if flag:
                  if trm:
                      cont = shortcuts.generate_container_curve()
                      cont.add(trm)
                      updated_trims.append(cont)
                  else:
                      updated_trims.append(trim)
  
          # Set updated trims
          obj.trims = updated_trims
docs: Fixes direction, connectivity and similar issues of the trim curves.
  
      This function works for surface trim curves consisting of a single curve.
  
      :param obj: input surface
      :type obj: abstract.Surface