Append to `ishape_last` only when date is missing

Otherwise the Fortran executable itself appends to `ishape_last.txt`.

Inst_eddies/inst_eddies_in.py

@@ -96,11 +96,11 @@ while True:
     else:
         print("inst_eddies.py: Missing file:", nc_file)
 
-    for orient in ["cyclo", "anti"]:
-        with open(f"SHPC_{orient}/ishape_last.txt", "a") as ishape_last, \
-             shapefile.Reader(f"SHPC_{orient}/extremum") as shpr:
-            n_shapes = len(shpr)
-            ishape_last.write(str(n_shapes - 1) + "\n")
+        for orient in ["cyclo", "anti"]:
+            with open(f"SHPC_{orient}/ishape_last.txt", "a") as ishape_last, \
+                 shapefile.Reader(f"SHPC_{orient}/extremum") as shpr:
+                n_shapes = len(shpr)
+                ishape_last.write(str(n_shapes - 1) + "\n")
 
     my_date += datetime.timedelta(1)
     if my_date > last_date: break