Generates a preview of src_path in the requested format.
  :returns: A list of preview paths, one for each page.

def preview(src_path):
  ''' Generates a preview of src_path in the requested format.
  :returns: A list of preview paths, one for each page.
  '''
  previews = []

  if sketch.is_sketchfile(src_path):
    previews = sketch.preview(src_path)

  if not previews:
    previews = quicklook.preview(src_path)

  previews = [safely_decode(preview) for preview in previews]

  return previews