Absolute path of the GSR file. Empty string if file is not present.

def gsr_path(self):
        """Absolute path of the GSR file. Empty string if file is not present."""
        # Lazy property to avoid multiple calls to has_abiext.
        try:
            return self._gsr_path
        except AttributeError:
            path = self.outdir.has_abiext("GSR")
            if path: self._gsr_path = path
            return path