new_contents: # vim: ft=python fileencoding=utf-8 sw=4 et sts=4
  """Wrapper functions for the _image_enhance C extension."""
  
  from gi.repository import Gdk
  
  from vimiv import _image_enhance
  
  def enhance_bc(pixbuf, brightness, contrast):
      """Enhance brightness and contrast of a GdkPixbuf.Pixbuf.
  
      Args:
          pixbuf: Original GdkPixbuf.Pixbuf to work with.
          brightness: Integer value between -127 and 127 to change brightness.
          contrast: Integer value between -127 and 127 to change contrast.
      Return:
          The enhanced GdkPixbuf.Pixbuf
      """
      # Work with Cairo surface as this can be transformed from and to bytes
      # quickly
      surface = Gdk.cairo_surface_create_from_pixbuf(pixbuf, 1, None)
      width = surface.get_width()
      height = surface.get_height()
      data = surface.get_data().tobytes()
      # Update plain bytes using C extension
      data = _image_enhance.enhance_bc(data, brightness, contrast)
      surface = surface.create_for_data(data, surface.get_format(), width,
                                            height, surface.get_stride())
      # Create pixbuf from updated surface
      return Gdk.pixbuf_get_from_surface(surface, 0, 0, width, height)
  
subject: Add python wrapper for C extension