def assertvalidimage(self, filename): if not os.path.isfile(filename): raise IOError(filename + " does not exist.") if "OpenEXR" in self.backends: if not exr.isOpenExrFile(filename): raise IOError(filename + " cannot be opened using OpenEXR.") elif "VTK" in self.backends: reader = self._make_reader(filename) if not reader.CanReadFile(filename): raise IOError("VTK Cannot open file " + filename) elif "PIL" in self.backends: try: PIL.Image.open(filename) except IOError: raise else: raise RuntimeError( "Warning: need OpenEXR or PIL or VTK to validate file store")