The isinstance() function in Python is used to check if an object is an instance of a specified type or class. When checking for multiple types, we can optimize our code by using a tuple of types instead of multiple isinstance() calls or conditions.

Let’s break it down:

1. Traditional approach (less efficient):

def is_number(num):
    return isinstance(num, int) or isinstance(num, float)
​
print(is_number(2))    # True
print(is_number(1.5))  # True
print(is_number("2"))  # False

2. Optimized approach using a tuple:

def is_number(num):
    return isinstance(num, (int, float))
​
print(is_number(2))    # True
print(is_number(1.5))  # True
print(is_number("2"))  # False

Benefits of using a tuple:

1. Conciseness: The code is more readable and compact.
2. Performance: It’s slightly more efficient, especially when checking against many types.
3. Maintainability: Easier to add or remove types to check against.

You can extend this concept to check for more types:

def is_sequence(obj):
    return isinstance(obj, (list, tuple, str))

print(is_sequence([1, 2, 3]))  # True
print(is_sequence((1, 2, 3)))  # True
print(is_sequence("123"))      # True
print(is_sequence(123))        # False

For broader type checking, use Python’s abstract base classes:

from collections.abc import Sequence

def is_sequence(obj):
    return isinstance(obj, Sequence)

print(is_sequence([1, 2, 3]))  # True
print(is_sequence((1, 2, 3)))  # True
print(is_sequence("123"))      # True
print(is_sequence(123))        # False

In this case, we’re checking if an object is a Sequence (like lists, tuples, or strings).