Read the configuration file

def read_file(self):
        """ Read the configuration file
        """

        # don't try to parse config file if we don't have one set
        if not self._cfg_path:
            return

        try:
            cfg_fp = open(self._cfg_path, 'r')
            self.readfp(cfg_fp)
        except IOError as exc:
            raise NipapConfigError(str(exc))