def __init__(self, internal, iid_indexer, sid_indexer):
'''
an indexer can be:
an integer i (same as [i])
a slice
a list of integers
a list of booleans
'''
self._internal = internal
self._iid_indexer = SnpReader._make_sparray_or_slice(iid_indexer)
self._sid_indexer = SnpReader._make_sparray_or_slice(sid_indexer)
