How to dynamically add items to a list in Python based on a condition?

[SubhanUllah]

my_list = ["A","B","C","Dummy"] 
junk_list = [] 
while True: 
    new_value = input("Enter a value 'quit' to end:") 
    if new_value == "quit": 
        break 
    if new_value.isalpha(): 
        my_list.append(new_value) 
    else: 
        junk_list.append(new_value) 
print(f"Alpha list is: {my_list}") 
print(f"Junk List is: {junk_list}") 

Output

Enter a value 'quit' to end:dddd 
Enter a value 'quit' to end:tttt 
Enter a value 'quit' to end:555 
Enter a value 'quit' to end:@#44 
Enter a value 'quit' to end:quit 
Alpha list is: ['A', 'B', 'C', 'Dummy', 'dddd', 'tttt'] 
Junk List is: ['555', '@#44']