<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def ft2file(self, **kwargs):
 """ return the name of the input ft2 file list """

        kwargs_copy = self.base_dict.copy()
        kwargs_copy.update(**kwargs)
        kwargs_copy['data_time'] = kwargs.get(
            'data_time', self.dataset(**kwargs))
        self._replace_none(kwargs_copy)        
        localpath = NameFactory.ft2file_format.format(**kwargs_copy)
        if kwargs.get('fullpath', False):
            return self.fullpath(localpath=localpath)
        return localpath