core_utilites += del_nested_item_from_index_sequence

This commit adds the missing 'del_nested_item_from_index_sequence',
which complements 'get_nested_item_from_index_sequence' and
'set_nested_item_from_index_sequence'. It was a missing counterpart and
has been added as a patch to 'mutwo.abjad' in mutwo-org/mutwo.abjad@bdfb37e.
Now it's officially part of 'mutwo.core'.

mutwo/core_utilities/tools.py

@@ -26,6 +26,7 @@
     "find_closest_item",
     "get_nested_item_from_index_sequence",
     "set_nested_item_from_index_sequence",
+    "del_nested_item_from_index_sequence",
     "find_numbers_which_sums_up_to",
     "call_function_except_attribute_error",
     "round_floats",
@@ -396,6 +397,34 @@ def set_nested_item_from_index_sequence(
             sequence = sequence[index]
 
 
+def del_nested_item_from_index_sequence(
+    index_sequence: typing.Sequence[int],
+    sequence: typing.MutableSequence,
+) -> None:
+    """Delete item in nested Sequence.
+
+    :param index_sequence: The indices of the nested item which shall be deleted.
+    :type index_sequence: typing.Sequence[int]
+    :param sequence: A nested sequence.
+    :type sequence: typing.MutableSequence[typing.Any]
+
+    **Example:**
+
+    >>> from mutwo import core_utilities
+    >>> nested_sequence = [1, 2, [4, [5, 1], [9, [3]]]]
+    >>> core_utilities.del_nested_item_from_index_sequence((2, 2, 0), nested_sequence)
+    >>> nested_sequence
+    [1, 2, [4, [5, 1], [[3]]]]
+    """
+
+    index_count = len(index_sequence)
+    for index_index, index in enumerate(index_sequence):
+        if index_count == index_index + 1:
+            sequence.__delitem__(index)
+        else:
+            sequence = sequence[index]
+
+
 def round_floats(
     number_to_round: core_constants.Real, n_digits: int
 ) -> core_constants.Real:

tests/utilities/tools_tests.py

@@ -129,6 +129,16 @@ def test_set_nested_item_from_index_sequence(self):
         core_utilities.set_nested_item_from_index_sequence((2, 2, 0), nested_sequence, 100)
         self.assertEqual(nested_sequence[2][2][0], 100)
 
+    def test_del_nested_item_from_index_sequence(self):
+        seq = [1, [2, 3, [4]]]
+        d = core_utilities.del_nested_item_from_index_sequence
+        d((1, 1), seq)
+        self.assertEqual(seq, [1, [2, [4]]])
+        d((1, 1, 0), seq)
+        self.assertEqual(seq, [1, [2, []]])
+        d((0,), seq)
+        self.assertEqual(seq, [[2, []]])
+
     def test_find_numbers_which_sums_up_to(self):
         self.assertEqual(
             core_utilities.find_numbers_which_sums_up_to(3), ((3,), (1, 2), (1, 1, 1))