<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def adorable(identifier, size):
    '''
    Adorable Avatars provider

    Simply redirect to the external API.

    See: http://avatars.adorable.io/
    '''
    url = ADORABLE_AVATARS_URL.format(identifier=identifier, size=size)
    return redirect(url)