Python implementation of the array translation K-bit problem

def move(ls: list, offset):
    """
    The sum of the original index of the element + the number of displacements (positive for right shift, negative for left shift) is solved for the remainder about the length of the array (the modulus of the array), i.e. the index of the element after displacement.
    The new index is then sorted in ascending order, removing the index, which is the new array after the displacement
    :param ls.
    :param offset.
    :return.
    """
    mod = len(ls)
    ids = [[(item[0]+offset)%mod, item[1]] for item in enumerate(ls)]
    (key=lambda item: item[0])
    return [item[1] for item in ids]

def move2(ls: list, offset):
    """
    Segmented inversion, bounded by the number of displacements (to modulo the remainder), inverts the two subarrays separately, and then inverts them as a whole
    :param ls.
    :param offset.
    :return.
    """
    mod = len(ls)
    offset = offset % mod
    tail = list(reversed(ls[mod-offset:]))
    head = list(reversed(ls[:mod-offset]))
    return list(reversed(head+tail))

if __name__ == '__main__':
    nums = [8, 9, 10, 11]
    print(move(nums, 1))
    print(move2(nums, 1))

    print(move(nums, -1))
    print(move2(nums, -1))
    """
	[11, 8, 9, 10]
	[11, 8, 9, 10]
	[9, 10, 11, 8]
	[9, 10, 11, 8]
	"""

# Method I
# -*- coding:utf-8 -*-
def rightShift(arr,k):
    if arr == None:
        print("The parameters are not legal!")
        return
    lens = len(arr)
    k %= lens #Because K is not necessarily less than N and may be greater than or equal to N, when K ≥ N, shifting right by K-N has the same effect as shifting right by K bits
    while k != 0: # Shift right by k bits
        tmp = arr[lens-1] The last element of the #array is placed in a temporary variable
        i = lens-1
        while i > 0:
            arr[i] = arr[i-1] # All elements moved back
            i -= 1
        arr[0] = tmp # The first element is the value of the initial last element
        k -= 1
 
if __name__ == "__main__":
    k = 4
    arr = ['a','b','c','d','1','2','3','4']
    rightShift(arr,k)
    i = 0
    while i < len(arr):
        print(arr[i],end="")
        i += 1

# Method II
def reverse(arr,start,end):
    while start<end:
        temp = arr[start]
        arr[start] = arr[end]
        arr[end] = temp
        start += 1
        end -= 1
 
def rightShift(arr,k):
    if arr == None:
        print("The parameters are not legal!")
        return
    lens = len(arr)
    k %= lens
    reverse(arr,0,lens-k-1)
    reverse(arr,lens-k,lens-1)
    reverse(arr,0,lens-1)
 
if __name__ == "__main__":
    k = 4
    arr = ['a','b','c','d','1','2','3','4']
    rightShift(arr,k)
    i = 0
    while i < len(arr):
        print(arr[i],end="")
        i += 1