Binary to decimal conversion with Python

iterative-incomplete.py

def binary_to_decimal_iterative(binary):
    total = 0
    for i in range(len(binary)):
        if binary[i] == '1':
            pass

    return total

recursive-incomplete.py

def binary_to_decimal_recursive(binary):
    if len(binary) == 1:
        return int(binary)
    else:
        rest = binary_to_decimal_recursive(binary[1:])
        if binary[0] == '1':
            pass
        else:
            return rest