docs: def _get_new_watermark_size(self, size, mark_default_size):
          """
          New size can be passed as a pair of valuer (tuple) or
          a fsloat (persentage case)
          """
          if hasattr(size, "__getitem__"):
              # a tuple or any iterable already
              mark_size = size
          elif isinstance(size, float):
              mark_size = map(lambda coord: int(coord * size), mark_default_size)
          else:
              raise ImproperlyConfigured(
                  "Watermark sizes must be a pair " "of integers or a float number"
              )
          return mark_size