def _input_as_multifile(self, data):
        """For use with the -profile option

        This input handler expects data to be a tuple containing two
        filenames. Index 0 will be set to -in1 and index 1 to -in2
        """
        if data:
            try:
                filename1, filename2 = data
            except:
                raise ValueError, "Expected two filenames"

            self.Parameters['-in'].off()
            self.Parameters['-in1'].on(filename1)
            self.Parameters['-in2'].on(filename2)
        return ''