[web2py] how to restrict a field to be alphabet only

[Saurabh S]

how i am developing a system in which i require a validation on name
field...validation shoould be : the field should not accept
numbers ...it should only accept alphabets...i know this is possible
using IS_MATCH in web2py...i tried using


db.organisations.name.requires=[IS_MATCH('^[a-z]', error_message='This
is not a valid name')]


but it is not working


 please help me out.....