code: def check_compatibility(self, one_img, another_img=None):
          
          if another_img is None:
              if len(self.items) > 0:
                  another_img = self.items[0]
              else:
                  raise ValueError('self.items is empty, need an image to compare '
                                   'with {}'.format(repr_imgs(one_img)))
  
          try:
              if self.all_compatible:
                  check_img_compatibility(one_img, another_img)
              if self.mask is not None:
                  check_img_compatibility(one_img, self.mask, only_check_3d=True)
          except:
              raise
docs: Parameters
          ----------
          one_img: str or img-like object.
              See NeuroImage constructor docstring.
  
          anoter_img: str or img-like object.
              See NeuroImage constructor docstring.
              If None will use the first image of self.images, if there is any.
  
          Raises
          ------
          NiftiFilesNotCompatible
              If one_img and another_img aren't compatible.
  
          ValueError
              If another_img is None and there are no other images in this set.