Get a boto3 session

def _get_session(region, key, keyid, profile):
    '''
    Get a boto3 session
    '''
    if profile:
        if isinstance(profile, six.string_types):
            _profile = __salt__['config.option'](profile)
        elif isinstance(profile, dict):
            _profile = profile
        key = _profile.get('key', None)
        keyid = _profile.get('keyid', None)
        region = _profile.get('region', None)

    if not region and __salt__['config.option']('datapipeline.region'):
        region = __salt__['config.option']('datapipeline.region')

    if not region:
        region = 'us-east-1'

    return boto3.session.Session(
        region_name=region,
        aws_secret_access_key=key,
        aws_access_key_id=keyid,
    )