<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def load(self, filename, using=None, parser=None, **kwargs):
 """ Load data from file using a specified parser. Return value will be separated or sliced into a column list Parameters filename : string A data file path using : list of integer, slice instance, or None, optional A list of index or slice instance used to slice data into column If it is not specified, :attr:`using` specified in constructor will be used instead. parser : instance or None, optional An instance or registered name of parser class. If it is not specified, :attr:`parser` specified in constructor will be used instead. Returns ------- ndarray A list of numpy array """

        using = using or self.using
        parser = parser or self.parser
        if parser is None:
            raise AttributeError("A parser instance must be specified")
        # parse iterator with the specified parser
        data = parser.load(filename, **kwargs)
        # slice column by using
        return slice_columns(data, using)