fixup: use "is" and "is not" when comparing with None values

Co-authored-by: Jover Lee <[email protected]>

scripts/newreference.py

@@ -20,7 +20,7 @@ def new_reference(referencefile, outgenbank, outfasta, gene):
 
     # If user provides a --gene 'some name' is not found, print a warning and use the entire genome.
     # Otherwise do not print a warning.
-    if(gene != None and startofgene==None and endofgene==None):
+    if(gene is not None and startofgene is None and endofgene is None):
         print(f"ERROR: No '{gene}' was found under 'gene' or 'CDS' features in the GenBank file.", file=sys.stderr)
         sys.exit(1)