def iterative(arr, summation):
    """
    Perform Two Sum by Iterative Method.
    :param arr: Iterable of elements.
    :param summation: sum to be searched.
    :return: returns true if found, else return None.
    """
    hash = set()

    for i in range(len(arr)):
        temp = summation-arr[i]
        if temp>=0 and temp in hash:
            return True
        hash.add(arr[i])

    return False