tions on custom sequence
types.

In the table *s* is an instance of a mutable sequence type, *t* is any
iterable object and *x* is an arbitrary object that meets any type and
value restrictions imposed by *s* (for example, "bytearray" only
accepts integers that meet the value restriction "0 <= x <= 255").

+--------------------------------+----------------------------------+-----------------------+
| Operation                      | Result                           | Notes                 |
|================================|==================================|=======================|
| "s[i] = x"                     | item *i* of *s* is replaced by   |                       |
|                                | *x*                              |                       |
+--------------------------------+----------------------------------+-----------------------+
| "del s[i]"                     | removes item *i* of *s*          |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s[i:j] = t"                   | slice of *s* from *i* to *j* is  |                       |
|                                | replaced by the contents of the  |                       |
|                                | iterable *t*                     |                       |
+--------------------------------+----------------------------------+-----------------------+
| "del s[i:j]"                   | removes the elements of "s[i:j]" |                       |
|                                | from the list (same as "s[i:j] = |                       |
|                                | []")                             |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s[i:j:k] = t"                 | the elements of "s[i:j:k]" are   | (1)                   |
|                                | replaced by those of *t*         |                       |
+--------------------------------+----------------------------------+-----------------------+
| "del s[i:j:k]"                 | removes the elements of          |                       |
|                                | "s[i:j:k]" from the list         |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.append(x)"                  | appends *x* to the end of the    |                       |
|                                | sequence (same as                |                       |
|                                | "s[len(s):len(s)] = [x]")        |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.clear()"                    | removes all items from *s* (same | (5)                   |
|                                | as "del s[:]")                   |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.copy()"                     | creates a shallow copy of *s*    | (5)                   |
|                                | (same as "s[:]")                 |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.extend(t)" or "s += t"      | extends *s* with the contents of |                       |
|                                | *t* (for the most part the same  |                       |
|                                | as "s[len(s):len(s)] = t")       |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s *= n"                       | updates *s* with its contents    | (6)                   |
|                                | repeated *n* times               |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.insert(i, x)"               | inserts *x* into *s* at the      |                       |
|                                | index given by *i* (same as      |                       |
|                                | "s[i:i] = [x]")                  |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.pop()" or "s.pop(i)"        | retrieves the item at *i* and    | (2)                   |
|                                | also removes it from *s*         |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.remove(x)"                  | removes the first item from *s*  | (3)                   |
|                                | where "s[i]" is equal to *x*     |                       |
+--------------------------------+----------------------------------+-----------------------+
| "s.reverse()"                  | reverses the items of *s* in     | (4)                   |
|                                | place                            |                       |
+--------------------------------+----------------------------------+-----------------------+

Notes:

1. If *k* is not equal to "1", *t* must have the same length as the
   slice it is replacing.

2. The optional argument *i* defaults to "-1", so that by default the
   last item is removed and returned.

3. "remove()" raises "ValueError" when *x* is not found in *s*.

4. The "reverse()" method modifies the sequence in place for economy
   of space when reversing a large sequence.  To remind users that it
   operates by side effect, it does not return the reversed sequence.

5. "clear()" and "copy()" are included for consistency with the
   interfaces of mutable containers that don’t support slicing
   operations (such as "dict" and "set"). "copy()" is not part of the
   "collections.abc.MutableSequence" ABC, but most concrete mutable
   sequence classes provide it.

   Added in version 3.3: "clear()" and "copy()" methods.

6. The value *n* is an integer, or an object implementing
   "__index__()".  Zero and negative values of *n* clear the sequence.
   Items in the sequence are not copied; they are referenced multiple
   times, as explained for "s * n" under Common Sequence Operations.
aM