Single LinkedList - Testing for inserting and deleting

single_linkedlist.py

class LinkedList:
    def __init__(self, d):
        self.d = d
        self.r = None
    
    def append(self, d):
        self.r = LinkedList(d)


def print_list(alist):
    while alist:
        print(alist.d, end=' --> ')
        alist = alist.r
    print('None')

def append_list(alist, sequence):
    for d in sequence:
        alist.r = LinkedList(d)
        alist = alist.r 

def pop_list(alist):
    alist = alist.r
    return alist

def insert_list(alist, pos_d, ins_d):
    while alist:
        if alist.d == pos_d:
            org_r = alist.r
            alist.r = LinkedList(ins_d)
            next_list = alist.r 
            next_list.r = org_r
        alist = alist.r 

def delete_list(alist, pos_d):
    org_alist = alist
    if alist.d == pos_d:
        org_alist = alist.r 
    else:
        new_alist = alist
        alist = alist.r
        while alist:
            if alist.d == pos_d:
                new_alist.r = alist.r
                alist = new_alist.r            
            new_alist = alist
            if alist:
                alist = new_alist.r
            else:
                break
    return org_alist

org = LinkedList('a')
alist = org
alist.append('b')
alist = alist.r
alist.append('c')

print_list(org)

insert_list(org, 'b', 'bb')
print_list(org)

new_org = delete_list(org, 'c')
print_list(new_org)