Discussion on: What does the len() function do in Python ?

>>> a = [1, 2, 3, 4]
>>> len(a)
4
>>> a = "amalshaji"
>>> len(a)
9
>>> a = (1, 2, 3, 4)
>>> len(a)
4
>>> a = {1, 2, 3, 4}
>>> len(a)
4
>>> class Amal:
...     def __init__(self):
...             pass
...     def __len__(self):
...             return 5
...
>>> a = Amal()
>>> len(a)
5