Python’s exception-handling mechanism provides a structured way to detect, handle, and manage runtime errors without abruptly terminating the program. The complete exception-handling block architecture consists mainly of `try`, `except`, `else`, and `finally`. These blocks work together to separate normal program execution from error-handling operations and cleanup activities. In a Data Structures and Algorithms laboratory, exception handling is especially useful because programs frequently perform operations such as array indexing, stack and queue manipulation, searching, file processing, and input conversion, where invalid input or unexpected conditions may produce runtime exceptions. The `try` block contains the statements that may generate an exception. Python first executes the statements inside the `try` block. If no exception occurs, the statements are completed normally and the `except` block is skipped. If an exception occurs, Python immediately stops executing the remaining statements in the `try` block and searches for a matching `except` block. The appropriate `except` block then handles the exception. The `except` block is used to catch and handle an exception. It can be designed to handle a particular type of exception, such as `ValueError`, `IndexError`, `ZeroDivisionError`, or `KeyError`. Specific exception handling is generally preferred because it makes the program easier to understand and prevents unrelated errors from being hidden. The `else` block is executed only when the `try` block completes successfully without raising an exception. Therefore, it is useful for statements that should execute only after the risky operations in the `try` block have succeeded. Keeping successful-operation code in `else` also makes the boundary between potentially failing statements and normal processing clearer. The `finally` block contains statements that must be executed regardless of whether an exception occurs. It executes after the `try` and either the `except` or `else` block. It is commonly used for cleanup operations, such as closing files, releasing resources, disconnecting from a database, or displaying a final status message. Thus, `finally` provides an important guarantee that necessary cleanup code will be executed. The general architecture can be represented as: ```python try: # Statements that may cause an exception except SomeException: # Code for handling the exception else: # Code executed when no exception occurs finally: # Code executed in all cases ``` The operational flow can be understood through a stack example. Suppose a stack is implemented using a Python list. The user wants to remove an element from the stack. If the stack is empty, attempting to