
    Given a list of historical credit scores where scores at even positions represent successful loan completions, calculate the sum of favorable credit ratings (represented by even numbers) that occur at even-month intervals. This calculation will help assess the pattern of successful loan repayments from borrowers with good credit scores during even-numbered months.
    

    
def sum_even_and_even_index(arr):
    """
    Given a list of historical credit scores where scores at even positions represent successful loan completions, calculate the sum of favorable credit ratings (represented by even numbers) that occur at even-month intervals. This calculation will help assess the pattern of successful loan repayments from borrowers with good credit scores during even-numbered months.
    

    """
def sum_even_and_even_index(arr):
    """
    Given a list of historical credit scores where scores at even positions represent successful loan completions, calculate the sum of favorable credit ratings (represented by even numbers) that occur at even-month intervals. This calculation will help assess the pattern of successful loan repayments from borrowers with good credit scores during even-numbered months.
    

    """
    i = 0
    sum = 0
    for i in range(0, len(arr), 2):
        if arr[i] % 2 == 0:
            sum += arr[i]
    return sum