How do i validate a user input in python ? I am writing this code , the user has to put in their name, and it has to be two names separated by a space and the name should contain only letters 

```
def Name():
    n = 0
    name = input('name please\n>>')
    c = name.split(' ')
    while len(c) != 2:
        print('we need two names')
        name = input('name please\n>>')
        c = name.split(' ')

    while True:
        for i in name:
            if i not in r:
                n+=1
        if n > 0:
            print('Letters only')
        else:
            break

Name()

```