Inserts data into seq using cmp_func to determine the new
position. The sequence must already be sorted according to cmp_func;
otherwise the new position of data is undefined.
cmp_func is called with two items of the seq, and cmp_data.
It should return 0 if the items are equal, a negative value
if the first item comes before the second, and a positive value
if the second item comes before the first.
Inserts data into seq using cmp_func to determine the new position. The sequence must already be sorted according to cmp_func; otherwise the new position of data is undefined.
cmp_func is called with two items of the seq, and cmp_data. It should return 0 if the items are equal, a negative value if the first item comes before the second, and a positive value if the second item comes before the first.
Note that when adding a large amount of data to a #GSequence, it is more efficient to do unsorted insertions and then call glib.sequence.Sequence.sort or glib.sequence.Sequence.sortIter.