Hi,
eachoverlap returns you a list that contains pairs of intervals that have overlap, so each pair contains one interval from col and one interval from hhh. Since you only want the intervals from col here, you can take the first value in each pair:
first.(eachoverlap(col, hhh))
This will return a Vector{Interval{String}} i.e. a Vector containing the Intervals from col that have overlap with any in hhh.
If you want this as an IntervalCollection instead, you can instead do:
IntervalCollection{String}(c for (c, h) in eachoverlap(col, hhh))