This code implements a basic class, `MyClass`, that contains a...

This code implements a basic class, MyClass, that contains a method for finding two indices in its input list that add up to a target value.

Explanation:

1. Initialization (__init__ method):

   • The constructor takes a list vals as input and initializes two attributes:
     • self.lookup: An empty dictionary that will be used to store previously seen values and their indices from the vals list.
     • self.vals: Stores the input list vals.

2. method function:

   • The method takes a single argument target, which represents the target sum.
   • It iterates through the list self.vals using a for loop.
   • For each element in the list (referred to as num), it checks whether the difference between the target and the current number (target - num) exists as a key in self.lookup.
     • If it exists, it means the current number (num) and one of the previously seen numbers (retrieved via self.lookup) add up to the target. The indices of these two numbers are returned as a tuple.
   • If the condition is not met, the current number is added to self.lookup with its index as the value.

3. Usage (b = MyClass([10, 20, 10, 40])):

   • An instance b of the MyClass is created with the input list [10, 20, 10, 40], meaning self.vals is [10, 20, 10, 40].

4. Calling the method (res3 = b.method(30)[1]):

   • The method is called with a target sum of 30.
   • The function will iterate through the list and find two indices where the numbers add up to 30:
     • On the first iteration (i = 0), it looks at 10. Since 20 (30 - 10) is not in self.lookup, it adds {10: 0} to the dictionary.
     • On the second iteration (i = 1), it looks at 20. It finds that 30 - 20 = 10 is in self.lookup (from the previous iteration). The indices of the numbers 10 and 20 are (0, 1), so the function returns (0, 1).
   • The [1] part retrieves the second element of the tuple (the index of the second number), which is 1.

Final Outcome:

The value of res3 will be 1.