KMSMasterKeyProvider - requested master keys are generated before setting default region.

When using KMSMasterKeyProvider, can a CMK key alias be used as the key_id instead of the arn?

The KMS API GenerateDataKey operation accepts alias as the key_id. But it looks like the sdk expects the key_id to be an arn. If the key_id is not an arn, the init fails with the below error -

The below fails with an exception -

kwargs = dict(
    key_ids=["alias/cmk-alias"],
    region_names=["us-east-1"],
    botocore_session=existing_session
)
aws_encryption_sdk.KMSMasterKeyProvider(**kwargs)

UnknownRegionError: No default region found and no region determinable from key id: alias/cmk-alias

/usr/local/lib/python2.7/site-packages/aws_encryption_sdk/key_providers/kms.py:50:UnknownRegionError