Patching segmentlists in pycbc.workflow module

[Thomas-JACQUOT]

Standard information about the request

This is a bug fix (in order to fix issue #5004)

This change affects PyGRB's workflows

This change was proposed by @duncanmmacleod in #5004 in this comment.

Links to any issues or associated PRs

This is the linked issue : #5004

Testing performed

This change was tested by submitting a PyGRB workflow that succeed to start.

• The author of this pull request confirms they will adhere to the code of conduct

[spxiwh]

I would prefer the following:

if isinstance(segs, segments.segment):
    self.segment_list = segments.segmentlist([segs])
elif isinstance(segs, segments.segmentlist):
    self.segment_list = segs
else:
    if not isinstance(segs, list):
        segs = [segs]
    try:
        self.segment_list = segments.segmentlist(map(segments.segment, segs))
    except ValueError as exc:
        exc.args = (
            "segs input must be either igwn_segments.segment or "
            f"igwn_segments.segmentlist. Got {type(segs).__name__}.",
        )
        raise

which keeps the initial isinstance checks. The reason is that if we have a long list (which can be the case) the map thing will (I think) duplicate a bunch of stuff, and is potentially slow. Not copying the segmentlist object when we don't need to would be more efficient.

[spxiwh]

Looks good to me!