Fix argparse

tofil.py

@@ -123,4 +123,9 @@ if __name__ == "__main__":
 
     args = parser.parse_args()
 
+    if args.infile is None and args.outfile is None:
+        parser.error("One of --infile or --outfile is required")
+    if args.infile is None and args.source is None:
+        parser.error("Without infile, --source must be specified")
+ 
     create_filterbank(infile=args.infile, outfile=args.outfile, date=args.date, source=args.source)