def _parse(self):
        """read in a file and return a MOPFile object."""
        with open(self.filename, 'r') as fobj:
            lines = fobj.read().split('\n')

        # Create a header object with content at start of file
        self.header = MOPHeader(self.subfmt).parser(lines)

        # Create a data attribute to hold an astropy.table.Table object
        self.data = MOPDataParser(self.header).parse(lines)