Updated parse.py

-Renamed update_selection to _update_selection since it is "private"
-Simplified _update_selection

machine/scripture/parse.py

@@ -22,34 +22,32 @@ def get_books(books: Union[str, List[str]]) -> Set[int]:
             subtraction = True
             book_id = book_id[1:]
         if book_id == "NT":
-            book_set = update_selection(book_set, set(range(40, 67)), subtraction)
+            book_set = _update_selection(book_set, set(range(40, 67)), subtraction)
         elif book_id == "OT":
-            book_set = update_selection(book_set, set(range(1, 40)), subtraction)
+            book_set = _update_selection(book_set, set(range(1, 40)), subtraction)
         elif "-" in book_id:
             ends = book_id.split("-")
             if len(ends) != 2 or book_id_to_number(ends[0]) == 0 or book_id_to_number(ends[1]) == 0:
                 raise ValueError(f"{book_id} is an invalid book range.")
             if book_id_to_number(ends[0]) >= book_id_to_number(ends[1]):
                 raise ValueError(f"{book_id} is an invalid book range. {ends[1]} precedes {ends[0]}.")
-            book_set = update_selection(
+            book_set = _update_selection(
                 book_set, set(range(book_id_to_number(ends[0]), book_id_to_number(ends[1]) + 1)), subtraction
             )
         else:
             book_num = book_id_to_number(book_id)
             if book_num == 0:
                 raise ValueError(f"{book_id} is an invalid book ID.")
-            book_set = update_selection(book_set, {book_num}, subtraction)
+            book_set = _update_selection(book_set, {book_num}, subtraction)
     return book_set
 
 
-def update_selection(book_set: Set[int], book_nums: Set[int], subtraction: bool) -> Set[int]:
+def _update_selection(book_set: Set[int], book_nums: Set[int], subtraction: bool) -> Set[int]:
     if subtraction:
         if book_nums.issubset(book_set):
             book_set.difference_update(book_nums)
         else:
-            book_ids = set()
-            for book_num in book_nums:
-                book_ids.add(book_number_to_id(book_num))
+            book_ids = {book_number_to_id(book_num) for book_num in book_nums}
             raise ValueError(f"{book_ids} cannot be removed as it is not in the existing book selection.")
     else:
         book_set.update(book_nums)