Spike Wuhan is here
Use the BioPython Bio.pairwise2 program here
Yours sequence is the reference, the shorter Wuhan query is the query.
The genomic positions position1 and position2 will then be defined via the output of pairwise2, then cut it by using the genomic position -1 as follows:
spike = completegenome[int(position1)-1:int(position2)-1]
-1 is needed because lists start at 0 rather than 1.