MutableSequence

MutableSequence is an abstract base class found in Python's `collections.abc` module. It defines the interface for sequences that can be modified in place. Essentially, it represents a sequence data type that supports operations such as item assignment, appending, extending, and deleting elements. While Python's built-in list type is a concrete implementation of MutableSequence, other custom sequence types can inherit from it to ensure they behave like mutable sequences. The core methods expected of a MutableSequence include `__getitem__`, `__setitem__`, `__delitem__`, `insert`, `append`, `extend`, and `pop`. By adhering to the MutableSequence interface, developers can write code that works generically with any mutable sequence object, promoting flexibility and interoperability. This abstraction is crucial for building robust and adaptable Python programs that handle collections of ordered items.