Using Boto and Python to connect to a specific region

Here is my slightly inelegant but working code to connect to specific region without setting up a configuration file or altering the default in the library (the access keys you can find under the tab security credentials on :

aaaa = your AWS Access key
sssss = your Secret Amazon key

from boto.ec2.connection import EC2Connection
default_conn = EC2Connection('aaaaa','sssss')

regions = default_conn.get_all_regions()

for r in regions:
    print r.name
    if r.name == 'eu-west-1':
       conn = EC2Connection('aaaaa',’sssss',region =r)

print regions

rs = conn.get_all_security_groups()
print rs