How to get boto3.resource to use a profile from credentials file

boto3-resource-profile.py

# To get boto3.resource to use a profile name, one must first
# setup a default session.  The credentials provided during the
# session setup will be subsequently used by resource().
#
# See: https://github.com/boto/boto3/issues/21
#      https://github.com/boto/boto3/pull/69
boto3.setup_default_session(profile_name=self.dpkg.profile_name)
self.ec2 = boto3.resource('ec2', region_name=self.dpkg.region_name)
filters = [{'Name': 'instance-state-name', 'Values': ['running']}]
for inst in self.ec2.instances.filter(Filters=filters):
    if inst.public_ip_address == fapi.env.hosts[0]:
        break