user validation

username.py

#!/usr/bin/env python

import string

def check_length(s):
    '''return length
        
    >>> check_length('this is a string')
    16
    '''
    return len(s)
        
def check_start_with(s, token=' '):
    '''return False if string begins with token
        
    >>> check_start_with(' test')
    False
    >>> check_start_with('test')
    True
    '''
    return not s.startswith(token)
        
def check_ends_with(s, token=' '):
    '''return False if string begins with token
        
    >>> check_ends_with('test ')
    False
    >>> check_ends_with('test')
    True
    '''
    return not s.endswith(token)
        
def check_digits(s):
    '''return #digits in string
        
    >>> check_digits('abc123')
    3
    '''
    return len([i for i in s if i in string.digits])
        
def check_uppercase(s):
    '''return # of [A-Z] in string
        
    >>> check_uppercase('abcABC')
    3
    '''
    return len([i for i in s if i in string.ascii_uppercase])
        
def check_lowercase(s):
    '''return # of [A-Z] in string
        
    >>> check_lowercase('abcABC')
    3
    '''
    return len([i for i in s if i in string.ascii_lowercase])
        
def get_occurence(s, token):
    '''get # tokens in string
        
    >>> get_occurence(r'1..@@__--', '@')
    2
    >>> get_occurence(r'1..@@__--', '_')
    2
    '''
    return s.count(token)

checks = [check_lowercase, check_start_with, check_ends_with, check_digits,
          check_uppercase, check_lowercase]

user = 'sometestuser@123ABC'
result=[]
for c in checks:
        result.append(c(user))

print result

        
if __name__ == "__main__":
        import doctest
        doctest.testmod()