Remove argument `i_slice` of `ishape_range`

Return `i_slice` instead. Since getting `i_slice` is now cheaper.

Common/util_eddies.py

@@ -254,16 +254,16 @@ class SHPC_class:
 
         return i_slice, ishape
 
-    def ishape_range(self, date, i_slice, orientation):
+    def ishape_range(self, date, orientation):
         """Returns an empty list if ishape_last was not found and could not be
-        created. Crashes if i_slice is not None and date is not in i_slice.
+        created.
 
         """
 
-        i_slice, ishape_start = self.comp_ishape(date, 1, orientation, i_slice)
+        i_slice, ishape_start = self.comp_ishape(date, 1, orientation)
 
         if ishape_start is None:
-            return []
+            return i_slice, []
         else:
             ishape_stop = (
                 self._ishape_last[i_slice][orientation][
@@ -271,7 +271,7 @@ class SHPC_class:
                 ]
                 + 1
             )
-            return range(ishape_start, ishape_stop)
+            return i_slice, range(ishape_start, ishape_stop)
 
 
 def in_window(point, window):

Inst_eddies/Analysis/plot_eddy_contours.py

@@ -36,7 +36,7 @@ def select_ishapes(
 
     """
 
-    ishape_list = SHPC.ishape_range(d, i_slice, orientation)
+    i_slice, ishape_list = SHPC.ishape_range(d, orientation)
 
     if window is None:
         ishape_list_filt = ishape_list

Inst_eddies/Analysis/write_date_range.py

@@ -46,7 +46,7 @@ for orientation in ["Anticyclones", "Cyclones"]:
         for my_date in range(args.date_start, date_stop):
             eddy_index = 0
 
-            for ishape in SHPC.ishape_range(my_date, i_slice, orientation):
+            for ishape in SHPC.ishape_range(my_date, orientation)[1]:
                 eddy_index += 1
 
                 for sr, w in zip([extremum.shapeRecord(ishape),