What is __repr__?

The __repr__ method in Python is a special method that returns a string representation of an object. This method is called by built-in functions and operators that need to convert the object to a string for display.

Here are the steps to understand __repr__:

1. __repr__ is a built-in function in Python, used for string representation of an object.
2. The __repr__ method returns a printable representational string of the given object.
3. This method is used to output detailed information about the object and is mainly used for debugging purposes.
4. If we did not define __repr__ method in our class, Python will use default method which doesn’t provide a human-readable output.
5. We can override this method in our classes to control what it should return, and it should ideally return a string which can be used to recreate the object.
6. The __repr__ method is also used as a debugging tool as it's a bit more explicit than __str__.

Here is an example:

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def __repr__(self):
        return f'Person(name={self.name}, age={self.age})'

p = Person('John', 30)
print(p)  # Outputs: Person(name=John, age=30)

In this example, the __repr__ method returns a string that looks like a valid Python expression. It includes the name of the class, and some additional information about its state (the name and age of the person). When we print the object, Python uses this string to represent the object.