def _validate_source(self, source):
        """
        Verify that all sources in the source tuple are provided by the
        dataset. Raise an error if some requested source is not available.

        Parameters
        ----------
        source : `tuple` of `str`
            Requested sources
        """
        for s in source:
            try:
                self.data_specs[1].index(s)
            except __HOLE__:
                raise ValueError("the requested source named '" + s + "' " +
                                 "is not provided by the dataset")
dataset/ETHPy150Open jfsantos/ift6266h14/old/pylearn2_timit/timitlpc.py/TIMITlpc._validate_source