At many instances, we get a need to access an object like an iterator. One way is to form a generator loop but that extends the task and time taken by the programmer. Python eases this task by providing a built-in method __iter__() for this task.
The __iter__() function returns an iterator for the given object (array, set, tuple, etc. or custom objects). It creates an object that can be accessed one element at a time using __next__() function, which generally comes in handy when dealing with loops.

Python iter() and next() are two special methods that are used to implement an iterator in Python. An iterator is an object that allows us to loop over a collection of data.

The iter() method is used to return an iterator object. This method is called when we use the iter() function on an object. The iter() method should return an object that has a next() method.

The next() method is used to return the next value from the iterator. When we call the next() method on an iterator, it should return the next value in the collection. If there are no more values, it should raise a StopIteration exception.

To convert an object into an iterator in Python, we need to define the iter() and next() methods in the object's class. The iter() method should return the object itself, and the next() method should return the next value in the collection.

Here's an example of how to define an iterator in Python: 

class MyIterator:
    def __init__(self, data):
        self.data = data
        self.index = 0

    def __iter__(self):
        return self

    def __next__(self):
        if self.index >= len(self.data):
            raise StopIteration
        value = self.data[self.index]
        self.index += 1
        return value

In this example, we define a class called MyIterator that takes a collection of data as input. The iter() method returns the iterator object itself, and the next() method returns the next value in the collection. We can use this iterator by creating an instance of the MyIterator class and then looping over it using a for loop: 

my_iterator = MyIterator([1, 2, 3, 4, 5])
for value in my_iterator:
    print(value)

This will output the values 1, 2, 3, 4, and 5.