Test, validate and match regular expressions
Matches a specific file naming convention for a "GapList" report, likely used in a CDPHP healthcare or insurance system. It expects the exact prefix "CDPHP_SPRPT_GapList_", followed by a 6-digit identifier, a constrained 2- or 3-digit number (16-21 or 100-119), another 9-digit sequence, a ".txt" extension, and a trailing space. It is useful for validating or extracting these specific report file names across multiple lines of text.