`len()` is a built-in function in Python 3\. This method returns the length (the number of items) of an object. It takes one argument `x`.
## Arguments
It takes one argument, `x`. This argument may be a sequence (such as a string, bytes, tuple, list, or range) or a collection (such as a dictionary, set, or frozen set).
## Return Value
This function returns the number of elements in the argument which is passed to the `len()` function.