Parse the files indicated in opts['src'] and load them into a python
        object for transport

def _load_files(self):
        '''
        Parse the files indicated in opts['src'] and load them into a python
        object for transport
        '''
        files = {}
        for fn_ in self.opts['src']:
            if os.path.isfile(fn_):
                files.update(self._file_dict(fn_))
            elif os.path.isdir(fn_):
                salt.utils.stringutils.print_cli(
                    fn_ + ' is a directory, only files are supported '
                    'in non-chunked mode. Use "--chunked" command '
                    'line argument.')
                sys.exit(1)
        return files