array_values = [[0], [0,0], [1,2], [3,1,2], [1,2,3], [4,6,2,1], [8,9,0,2,1]]

def peakfinder(array):
    if len(array) == 0:
        print("You entered an empty error !!")
        raise ValueError
    if len(array) == 1:
        return array[0]
    if len(array) == 2:
        return max(array)
    mid_element_index = len(array) // 2
    mid_element = array[mid_element_index]
    if mid_element >= array[mid_element_index + 1] and mid_element >= array[mid_element_index - 1] :
        return mid_element
    elif mid_element < array[mid_element_index + 1]:
        return array[mid_element_index + 1:]
    else:
        return array[ :mid_element_index]

for array in array_values:
    while type(array) != int:
        array = peakfinder(array)
    print("The peak value is", array)