Construct RecordSet from values

Looking for a way to lookupRecords of a table from set of values.
Migrating from Airtable, one of the columns have set of AT Id’s which land in csv as “val1, val2, val3”.
While importing I would love to apply formula which looks up these values in another table.

I have applied this formula:

def lookup_many(at_Image_RecId):
    return Images.lookupOne(atRecId=at_Image_RecId).id
imgRecords = map(lookup_many, rec.at_Images_RecId.split(", "))
return list(imgRecords)

I have actually forgotten to change field type to Reference list from previous Reference. It now worked as expected.