def __init__(self, steps_col, slc):
self._col = steps_col<EOL>self._idx = slc.indices(len(self._col))<EOL>self._flt = {<EOL>'<STR_LIT>': False,<EOL>'<STR_LIT>': False,<EOL>'<STR_LIT>': [],<EOL>'<STR_LIT>': lambda _: True,<EOL>}<EOL>self._dflt_func = self._flt['<STR_LIT>']<EOL>
Initialization of instances:

        Args:
            steps_col (:class:`_Steps` or :class:`_Snaps`): steps collection,
                i.e. :attr:`StagyyData.steps` or :attr:`StagyyData.snaps`
                attributes.
            slc (slice): slice of desired isteps or isnap.